build: Commitizen implementation

[12rambau]

• create a commitizen environment
• create a github action workflow:
  • locally run cz bump
  • push to main
  • triggers everything in this order -> bump tag -> bump changelog -> create Github release -> create pipy release
• document the release process in the doc

I folowed the requirements from https://commitizen-tools.github.io/commitizen/tutorials/github_actions/
It still need to be tested with an administrator of the repository as it request 2 extra secrets environment variables