ci: check PR & commit message formats

[Riernar]

In this PR, we partially implement the CI described in #23. We use the angular commit format to later be able to generate CHANGELOG.md using the generate-changelog NPM package.

• Add a pull request CI which verify that:
  • PR title & commit message follow angular's commit header format
  • github issue/PR reference explicitely reference the repository
  • Cleanup the README