Add support for release branches

[douglaslassance]

Currently, Gitalong only works for a trunk-based or feature branch development workflow. That's because any changes done by anyone else on any other branch result in protecting the files.

Release branches should not limit editing a file that is changed in any other branch or clone. In order to enable this workflow, we have to provide the ability to specify a release branch naming convention that will be treated differently by the system.