Refactor how public and tag timelines are queried

[Gargron]

Contains some minor behaviour changes:

• Excluded suspended accounts from public timelines (was not enforced previously)
• No longer show silenced user own posts in public timelines (silenced users can no longer make public posts anyway)
• Don't allow any/all/none filters in RSS and JSON-LD versions of the public hashtag resource
• Make JSON-LD version of public hashtag resource support min_id/since_id (consistently with outbox)

[ClearlyClaire]

I'm not sure I agree with the “Don't allow any/all/none filters in RSS and JSON-LD versions of the public hashtag resource” part, but otherwise it seems fine to me.

Minor remarks in inline comments.

Also, HashtagQueryService doesn't seem to be used anymore, but the PR doesn't remove its definition.

[Gargron]

I'm not sure I agree with the “Don't allow any/all/none filters in RSS and JSON-LD versions of the public hashtag resource” part

Even if you discard that joining multiple tags is a more expensive operation, I don't think it's right for a JSON-LD resource to represent a complex union of different collections... It should be 1:1, in my opinion. Also nobody knows this feature even exists.