Discuss: Determine the best ways to store annotation tags

Summary

While investigating the best way to store annotations #205091 (closed) the need to efficiently store annotation tags surfaced. This issue is to investigate the best ways to store tags.

Techincal details

Check this for the rationale behind storing annotations in postgres #205091 (comment 303145384).

Somebody from groupapm backend to fill the rest of this.

Screenshots

ER Model for annotations and tags