Create CI/CD-only projects

What does this MR do?

• Add ability to create a CI/CD-only project from a Git URL

When creating a new Project we need to set the new ci_cd_only attribute to true or 1

• Add ability to create a CI/CD-only project from GitHub Handled through !4762 (closed)
• Disable issues, merge requests, container registry, wiki, snippets
• Enable pull mirroring of the project
• Match the visibility of imported repo if importing from GitHub (Already implemented in the current importer)

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

Why was this MR needed?

Screenshots (if relevant)

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• API support added
• Tests added for this feature/bug
• Review
  • Has been reviewed by UX
  • Has been reviewed by Frontend
  • Has been reviewed by Backend
  • Has been reviewed by Database
• Conform by the merge request performance guides
• Conform by the style guides
• Squashed related commits together
• Internationalization required/considered
• If paid feature, have we considered GitLab.com plan and how it works for groups and is there a design for promoting it to users who aren't on the correct plan
• End-to-end tests pass (package-qa manual pipeline job)

What are the relevant issue numbers?

Closes #3839 (closed)