Create a push rule to check branch name

What does this MR do?

It creates a new push rule to check the branch name

Are there points in the code the reviewer needs to double check?

Don't think so, but it is my first contribution, so everything :)

Why was this MR needed?

At work we heavily use Gitlab and Gitlab CI (\o/) and we have a strictly policy for branch names (actually, for the beginning of the name) because we have different Gitlab CI jobs (feature / hotfix / docker / android etc etc) and I am tired to have to remember which names are allowed and which not

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests
  • Added for this feature/bug
  • All builds are passing
• Conform by the merge request performance guides
• Conform by the style guides
• Branch has no merge conflicts with master (if it does - rebase it please)
• Squashed related commits together

What are the relevant issue numbers?

Fixes #2293 (closed)