Determine if instance-level configuration is needed for Dedicated

Overview

We opted for using a feature flag to turn the pre-receive-secret-detection feature on/off on, however, there was a concern that feature flags do not work with GitLab Dedicated. For that, we need to determine if an instance-level configuration have to be used instead.

Please see parent epic for more details and considerations.

Prior Art

Please see #398192 (closed) for an example of how an instance-level configuration might be introduced.

Assistance Needed

Assistance from groupdedicated and/or groupdistribution is likely required.

Implementation Plan

• Find out if GitLab Dedicated supports feature flags. It does not.
• Reach out to groupdedicated and/or groupdistribution to:
  • Learn if there are immediate plans to support feature flags.
  • Consult with them on the best way forward if we are to have both instance-level configuration + project-level FF.
• Decide on the next steps and answer the following questions:
  • Shall we discard the feature flag proposal? No, we are not.
  • Shall we use an instance-level configuration instead? Yes, see discussion below.
  • Would both options work interchangeably, and can only one be used that fits our needs? Both options can work together.