Feature request from @darookee

It would be nice if tags could be added and updated on documents via the REST API, as well as searching/filtering the /api/documents by them.

Ticket spun off from this comment.

Please ensure your pull request adheres to the following guidelines:

Search previous suggestions before making a new one, as yours may be a duplicate.
Make an individual pull request for each suggestion.
New categories or improvements to the existing categorization are welcome.
Check your spelling and grammar.
The pull request and commit should have a useful title.
Add short description ab