Update search page to account for new searching method

[dessalines]

Requirements

• This is a feature request and not a bug report. Otherwise, please create a new bug report instead.
• Please check to see if this request (or a similar one) already exists.
• It's a single feature. Please don't request multiple features in one issue.

Describe the feature you'd like

The Search is deprecated in favor of using specific types, and the search_term, search_url_only, and search_post_url_only fields added to all these list endpoints.

This will also entail externalizing the filter bars for given listing types.

Context: LemmyNet/lemmy#6397

[Nutomic]

So you really intend to get rid of the All search in lemmy-ui? Meaning it only searches posts by default, and searching for comments, users or communities requires extra clicks?

Its really not a great idea to cripple the search like that, even Piefed users consider the Lemmy search "supremely excellent" (link), so we shouldnt downgrade it unnecessarily.

[dessalines]

Yep. There will be a dropdown with all the types, and it will show the appropriate filter bar given the specific type selected. It would be at most three clicks to search for other types of content: IE type something in the bar, click the type dropdown, then click comment.

I can't think of any case where you'd want to search for something, but have no idea what type it is. You almost certainly know the type of content before you search, and you likely don't want to see other types in those results. IE I want to find this person, I want to find this post, etc.

That weak use case, plus the performance tradeoff, plus the lack of specific filtering to me makes it not worth keeping.

[Nutomic]

Right it still works, but the problem is that it requires extra clicks. If I search for a specific user with a unique name, I just want to enter the name, click submit and immediately see the correct result. I shouldnt have to tell the website that it is a user. The general search also doesnt have any performance problems in 0.19.

Using specific searches with extra filters makes sense, but it shouldnt replace the general search.

[dessalines]

Still should be open, because I need to rework search to use the individual list endpoints.