Using `commitlint` require the users to include `templates/Git.yaml`
and `extends` the `.git:commitlint` job template.

We keep `templates/Lint/Commitlint.yaml` for backward compatibility.

* templates/Git.yaml: new git related job templates

* templates/Lint/Commitlint.yaml: define `commitlint` with the
  `.git:commitlint` job template for backward compatibility.

* .commitlintrc.yaml: move from JS to YAML.