Allow searching for hashtags in admin UI

[renchap]

Preliminary note

This issue is part of our "help wanted" issues. It represents something that we know we want to implement, and that is defined enough that a contributor can implement it in a way that it would get merged.

If you want to work on this, please add a comment saying so and ask any questions you need, then open a PR referencing this issue!

Description

There is currently no way to see the details about a tag (ex: /admin/tags/1) that is not trending (except by looking up it's tag ID in the database).

A new "Moderation > Hashtags" page should be added to the admin panel, with a field to search for an hashtag (maybe using the existing auto-complete endpoint from the composer?).

Clicking on a hashtag (or typing its full name?) should open the tag detail page.

This would solve #23923

Implementation notes

[ThisIsMissEm]

I'd be interested in working on this, provided I've financial backing (I'm a freelancer, so time is money)

[ThisIsMissEm]

@renchap would being able to preemptively "create" a hashtag before it's been used also be within the scope of work here? Same with splitting the "allow / disallow" usage of this hashtag into local and remote usage? e.g., #29264

[renchap]

@renchap would being able to preemptively "create" a hashtag before it's been used also be within the scope of work here?

Let's say it would be an additional feature. We did not discuss this internally but I can see how this could be useful

Same with splitting the "allow / disallow" usage of this hashtag into local and remote usage? e.g., #29264

Probably out of the scope as it has more impacts