Move local Tiller FF check to cluster level

What does this MR do?

This builds on the #209736 (closed) by making the feature flag specific to the entity that owns the cluster, as opposed to a global flag.

The idea is to make the flag default enabled at the instance level, but have a way to back out at the level of the entity that owns the cluster (can be a project, a group or the instance).

Screenshots

Group cluster with flag disabled

Group cluster with flag enabled

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

Availability and Testing

• [-] Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• [-] Label as security and @ mention @gitlab-com/gl-security/appsec
• [-] The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• [-] Security reports checked/validated by a reviewer from the AppSec team