Incorporate CI workflow to the training engine

[hajeressef]

What is DONE when a PR is opened, or converted to RTR, with the base branch being 'master' on the training engine:

• launch unit tests (excluding trainings) for the models whose one of the files are modified by the commits of the PR

When we want to update with a new picsellia version:

• find requirements files + update requirements files with new picsellia version if existing version different to the one given as argument
• create a new branch called picsellia-CI-v + version and commit and push new changes in reqs files
• rebuild + push test docker images in github actions

[This is applied to 3 yolov8 models + UNet]

• We manually launch integration tests, using the newly built test docker images.
• If all experiments status is "success" then we merge the pull request picsellia-CI-v + version to master and add the tag picsellia-v + version
• The tag should launch the rebuild + push of latest docker images

[hajeressef]

RTR https://github.com/picselliahq/picsellia-training-engine/pull/56