Geo: Test Blob Replicators more generically

What does this MR do?

• The next time a Replicator is added which includes BlobReplicatorStrategy, it should be easier to do so correctly.
• Begin documenting how to replicate a new kind of Blob.
• Automagically publish created events to remove a step to add a new kind of Model, since it will likely apply to most new Models.

This is already feature flagged under :geo_self_service_framework.

Closes #118745 (closed)

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