[FEATURE] Improve sx127x application to get data and verify data integrity

[acassis]

Is your feature request related to a problem? Please describe.

While testing two modules transmitting and receiving FSK data less than 1 meter (~ 3 ft) apart I noticed that sometimes the receiver module don't show any data and sometimes it was displaying wrong data:

Received:                                                                         
SNR  = 0                                                                          
RSSI = -90                                                                        
len  = 21                                                                         
0x00 0x01 0x02 0x03 0x04 0xb9 0x86 0x33 0x9f 0xf5                                 
0x0f 0x40 0xf3 0x3c 0xf8 0x0b 0x9e 0xee 0xfe 0x3f                                 
0xf2                                                                              
                                                                                  
wait 5 sec ...                                                                    
Waiting for data                                                                  
                                                                                  
Received:                                                                         
SNR  = 0                                                                          
RSSI = -101                                                                       
len  = 5                                                                          
0x00 0x01 0x02 0x03 0x06                                                          
                                                                                  
wait 5 sec ...                                                                    
Waiting for data                                                                  
                                                                                  
Received:                                                                         
SNR  = 0                                                                          
RSSI = -104                                                                       
len  = 5                                                                          
0x00 0x01 0x02 0x03 0x04                                                          
                                                                                  
wait 5 sec ...                                                                    
Waiting for data                                                                  
                                                                                  
Received:                                                                         
SNR  = 0                                                                          
RSSI = -105                                                                       
len  = 5                                                                          
0x00 0x01 0x02 0x03 0x04                                                          
                                                                                  
wait 5 sec ...                                                                    
Waiting for data                                                                  
                                                                                  
Received:                                                                         
SNR  = 0                                                                          
RSSI = -106                                                                       
len  = 5                                                                          
0x00 0x01 0x02 0x03 0x04                                                          
                                                                                  
wait 5 sec ...                                                                    
Waiting for data                                                                  
                                                                                  
Received:                                                                         
SNR  = 0                                                                          
RSSI = -106                                                                       
len  = 5                                                                          
0x00 0x01 0x02 0x03 0x04                                                          
                                                                                  
wait 5 sec ...                                                                    
Waiting for data                                                                  
                                                                                  
Received:                                                                         
SNR  = 0                                                                          
RSSI = -104                                                                       
len  = 5                                                                          
0x00 0x01 0x02 0x03 0x04                                                          
                                                                                  
wait 5 sec ...                                                                    
Waiting for data                                                                  
                                                                                  
Received:                                                                         
SNR  = 0                                                                          
RSSI = -105                                                                       
len  = 5                                                                          
0x00 0x01 0x02 0x03 0x04                                                          
                                                                                  
wait 5 sec ...                                                                    
Waiting for data                                                                  
                                                                                  
Received:                                                                         
SNR  = 0                                                                          
RSSI = -94                                                                        
len  = 21                                                                         
0x00 0x01 0x02 0x8b 0x04 0x39 0x76 0x3b 0x8d 0x0b                                 
0xce 0x55 0x5b 0xbf 0xb7 0xe9 0xa6 0x40 0x5e 0x7a                                 
0x3a                                                                              
                                                                                  
wait 5 sec ...                                                                    
Waiting for data                                                                  
                                                                                  
Received:                                                                         
SNR  = 0                                                                          
RSSI = -107                                                                       
len  = 5                                                                          
0x00 0x01 0x02 0x03 0x04                                                          
                                                                                  
wait 5 sec ...                                                                    
Waiting for data                                                                  
                                                                                  
Received:                                                                         
SNR  = 0                                                                          
RSSI = -105                                                                       
len  = 5                                                                          
0x00 0x01 0x02 0x03 0x04
``

### Describe the solution you'd like

After some testing I discovered that the default TX Power (set to 14 value) is too low, normally the receiver was showing -90 to -111 dBm. I suggest using a little bit higher value: currently I'm using the value 20 that turns on the PA, the the RSSI changed to -14 to -11. After it the modules always will communicate.

Also I suggest enabling the CRC (CONFIG_LPWAN_SX127X_CRCON = 1), although after increasing the power TX I didn't noticed any data corruption.

### Describe alternatives you've considered

_No response_

### Verification

- [x] I have verified before submitting the report.