WIP: Adding initial implementation of feature to enable setting default mr target branch per project
What does this MR do?
This MR adds a feature to enable users to set a default merge target branch on a per project basis. This is useful for some development workflows where the default_branch is less regularly the desired target. see #17909
- Create a new field on the project model
- Tie the field in with graphql
- Add a front-end component to project MR settings
- Create a method for updating the new field
- Link the new field to the front-end
Does this MR meet the acceptance criteria?
- Changelog entry
- Documentation (if required)
- Code review guidelines
- Merge request performance guidelines
- Style guides
- Database guides
- Separation of EE specific content