feat: Gitflow oriented gradle tasks

[VincentMasselis]

• [x] Create the git flow plugin
• [x] Tasks
• [x] Update the github plugin
• [x] Update the play store plugin
• [x] Prevent main to be updated with an identical version name (generated version code will be the same)
• [x] Promotes the artifact when the commit comes from a release/* branch and create release when the commit comes from an hotfix/* branch
• [x] Check github release notes generation and update if release/* contains multiple commits
• [x] Update documentation
• [x] Automatic release note generation with 500 characters max

[github-actions[bot]]

Test Results

 38 files  ±0   38 suites  ±0   3m 32s :stopwatch: +11s  61 tests ±0   61 :white_check_mark: ±0  0 :zzz: ±0  0 :x: ±0  182 runs  ±0  182 :white_check_mark: ±0  0 :zzz: ±0  0 :x: ±0 

Results for commit 6a6de2a7. ± Comparison against base commit c7afa007.

:recycle: This comment has been updated with latest results.