Allow test resources to be reused

What does this MR do and why?

Allows resources to be shared between tests where possible/safe

• Adds a ReusableProject resource
• Updates a couple of tests to use the new resource
• Defers cleaning up reusable resources until after the suite completes

See https://gitlab.com/gitlab-org/quality/team-tasks/-/issues/1032

How to set up and validate locally

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.