Make Object Storage synchronization in Geo Nodes configurable via Admin UI

What does this MR do?

Incredibly, I accidentally deleted the original MR: https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/15000. I still don't know how it happened.

It was 100% ready for merge, and I was just waiting for the pipeline to go green.

This MR extracts the Admin UI and DB changes needed for https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/13997.

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content

Performance 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

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

Related #10586 (closed)