Deploy lambda: fix the 'end_script' deploy parameter

[nikolayilyin]

We need to be able to specify a script to be run after a simulation (on aws/google cloud):

1. add 'end_script' parameter to gradle deploy command in order to send a script name to the lambda
2. check 'end_script' in the deploy lambda in order to be sure the file by this path is exist, if it is not - return an error with an explanation that path is invalid
3. put the end_script in the deploy lambda before the part which do copy to S3 storage
4. add an example of post processing: shell script - src/main/bash/post_processing/example.sh python script - src/main/python/post_processing/read_events_head.py the shell script should find the output folder and call the python script, the python script should find events file in the output folder and if the file exist then read with pandas first few rows of events file.
5. by-default the 'end_script' parameter should be an empty string
6. add a documentation entry about this parameter and mention an example script