Solve git subfolder dependency install of dkmanager_worker

[Benvii]

With setup.cfg I didn't find anyway to install dependency package present inside a git subdirectory. We should probably try to move to the modern pyproject.toml configuration files.

Actually what work for this dependency is :

pip install -e "git+https://github.com/mdl29/donkeycarLPH.git@main#egg=dkmanager_worker&subdirectory=dkmanager_worker"

And it was added to backend/Readme.md and mycar ansible tasks.

The objective of this ticket is to find a better way to handle this dependency without having to run pip individually.