Configure integrations link experiment (repo_integrations_link) [RUN ALL RSPEC] [RUN AS-IF-FOSS]

What does this MR do?

Named: repo_integrations_link

Part of https://gitlab.com/gitlab-org/gitlab/-/issues/285558

This adds an experiment that adds a "Configure Integrations" button on the project view that simply links to the integrations settings page. The button is only ever presented to those who would have access to it (as an admin of the project). The rollout plan will be 50/50%.

Screenshots (strongly suggested)

before	after

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content