Allow to specify the name of requirements.txt file

[kirsanium]

При генерации кода в гитхаб экшнс затираются мои зависимости (например, я добавил pytz)

[php-coder]

@kirsanium The default behavior has been changed to not overwrite files by default. In order to overwrite them, the new --overwrite option has been introduced.

[php-coder]

--overwrite option has been removed as it doesn't solve the issue properly:

1. when we have a generated app and we modified only one file (for example, requirements.txt), using --overwrite option lead us to the situation when no files generated at all. So, in fact, modification of one file exclude the application completely from auto generation
2. the case when we want to have custom modifications to requirements.txt was still not addressed.

One way to solve this, was proposed by @kirsanium where we tell query2app to create requirements.txt with another name and include it from user managed requirements.txt with (-r option).