Geo: Add missing registry table indexes

Problem

I noticed that job_artifact_registry, lfs_object_registry, and file_registry do not have indexes on the state field. As far as I know, these missing indexes are not an immediate blocker for anything. But the state field is commonly queried, and I would expect these indexes to help performance here and there. Also we are exposed to future hidden performance bugs due to this issue.

Proposal

• Add those 3 indexes.
• Look for more indexes which are specified in the instructions to add a data type here and here, but which unexpectedly do not exist in Geo's structure.sql.