Container shutdown speed fix

[Deelite34]

Story / Bug id:

N/A

Description:

Adds minor optimization and speeds up frontend and backend applications shutdown in docker, by making them correctly receive SIGTERM signal from docker.

exec makes frontend/backend app commands executed in entrypoint scripts main processes instead subprocesses of entrypoint script in their containers, which fails to pass termination signals to them.

init: true setting in docker makes apps executed with the entrypoint script subprocesses of dummy PID: 1 init process that will pass signals correctly to the application subprocess and avoid theorical issues with making frontend/backend app main processes.

https://buddy.works/tutorials/optimizing-dockerfile-for-node-js-part-1#reducing-the-number-of-processes
https://hynek.me/articles/docker-signals/#bonus-best-practice-let-someone-else-be-pid-1
https://engineeringblog.yelp.com/2016/01/dumb-init-an-init-for-docker.html

Before:

After:

Migrations:

N/A

New imports / dependencies:

N/A

What tests do I need to run to validate this change:

N/A