feature: merge tianmu.log into mysqld.log, just like innodb does.

[hustjieke]

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

Now Tianmu engine has its own log file, see next:

root@gry:/github/stonedb/build/install8# ls log/
mysqld.log  query.log  slow.log  tianmu.log  trace.log

The log infos in tianmu.log:

[2022-09-28 08:34:16.036979] [375094] [INFO] [kv_store.cpp:55] MSG: First init rocksdb, create default cloum family
[2022-09-28 08:34:16.067569] [375094] [INFO] [mapped_circular_buffer.h:75] MSG: created delayed buffer file TIANMU_INSERT_BUFFER with size 512MB
[2022-09-28 08:34:16.067615] [375094] [INFO] [mapped_circular_buffer.h:211] MSG: insert buffer address 0x7f9d77fb0000
[2022-09-28 08:34:16.067721] [375094] [INFO] [memory_handling_policy.cpp:94] MSG: Adjusted Main Heap size = 16832790528
[2022-09-28 08:34:16.067749] [375094] [INFO] [memory_handling_policy.cpp:95] MSG: Adjusted LT Heap size = 0
[2022-09-28 08:34:16.106856] [375094] [INFO] [engine.cpp:930] MSG: Cachefolder cache does not exist. Trying to create it.
[2022-09-28 08:34:16.107099] [375094] [INFO] [engine.cpp:235] MSG: Tianmu engine started.
[2022-09-28 08:34:16.107157] [375094] [INFO] [engine.cpp:236] MSG: Tianmu data directories:
[2022-09-28 08:34:16.107166] [375094] [INFO] [engine.cpp:237] MSG:   {
[2022-09-28 08:34:16.107177] [375094] [INFO] [engine.cpp:239] MSG:     default
[2022-09-28 08:34:16.107185] [375094] [INFO] [engine.cpp:246] MSG:   }
[2022-09-28 08:34:16.107195] [375094] [INFO] [engine.cpp:248] MSG: Tianmu thread pool for background load, size = 16
[2022-09-28 08:34:16.107204] [375094] [INFO] [engine.cpp:250] MSG: Tianmu thread pool for load, size = 32
[2022-09-28 08:34:16.107213] [375094] [INFO] [engine.cpp:251] MSG: Tianmu thread pool for query, size = 32
[2022-09-28 08:34:16.107565] [375094] [INFO] [tianmu_handler_com.cpp:227] MSG:  
-----------------------------------------------------------------------------------------------------------
    ######  ########  #######  ##     ## ######## ######   ######   
   ##    ##    ##    ##     ## ####   ## ##       ##    ## ##    ## 
   ##          ##    ##     ## ## ##  ## ##       ##    ## ##    ## 
    ######     ##    ##     ## ##  ## ## ######   ##    ## ######## 
         ##    ##    ##     ## ##   #### ##       ##    ## ##    ##  
   ##    ##    ##    ##     ## ##    ### ##       ##    ## ##    ##    
    ######     ##     #######  ##     ## ######## ######   ######    
-----------------------------------------------------------------------------------------------------------

Describe the solution you'd like

We should merge Tianmu log infos into mysqld.log, like innodb does:

2022-09-28T08:35:18.761967Z 0 [System] [MY-010116] [Server] /github/stonedb/build/install8/bin/mysqld (mysqld 8.0.30-debug) starting as process 376652
2022-09-28T08:35:18.765872Z 0 [Warning] [MY-010339] [Server] Using pre 5.5 semantics to load error messages from /github/stonedb/build/install8/share/english/. If this is not intended, refer to the documentation for valid usage of --lc-messages-dir and --language parameters.
2022-09-28T08:35:18.895935Z 0 [Warning] [MY-013267] [InnoDB] The setting INNODB_UNDO_TABLESPACES is deprecated and is no longer used.  InnoDB always creates 2 undo tablespaces to start with. If you need more, please use CREATE UNDO TABLESPACE.
2022-09-28T08:35:18.896063Z 0 [Warning] [MY-013907] [InnoDB] Deprecated configuration parameters innodb_log_file_size and/or innodb_log_files_in_group have been used to compute innodb_redo_log_capacity=2147483648. Please use innodb_redo_log_capacity instead.
2022-09-28T08:35:18.904708Z 1 [System] [MY-013576] [InnoDB] InnoDB initialization has started.
2022-09-28T08:35:20.268891Z 1 [System] [MY-013577] [InnoDB] InnoDB initialization has ended.

Describe alternatives you've considered

Additional context

[hustjieke]

After merge tianmu.log into mysqld.log, port this change into stonedb-5.7-dev branch.