Add status checks and approval rules to branch details

What does this MR do and why?

Adds labels, status checks and approval rules to branch details

Screenshots or screen recordings

How to set up and validate locally

1. Make sure that EE features are enabled
2. Enable :branch_rules FF
3. Go to Project > Settings > Repository
4. Expand branch rules section
5. In case of lack of test data edit Branch Protection section to have branches with different protections.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #372844 (closed)