Global/sub search

[ghost]

Is your feature request related to a problem? Please describe.
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The app currently does not have an option to search globally.

Describe the solution you'd like
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Dedicated search button for global search, separate or combined with subreddit search.

Describe alternatives you've considered
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The Dawn dropdown could be rethinked somewhat if the sub search isn't there. It's quite a lot of space to be only used for subreddits. It has a lot of potential.

The refresh button could be moved to 1 row lower where currently the sorting button is. The design of the icon could be smaller and more minimal of course. This way we can gain space for the new search button.

In the search dropdown could be options to sort by type (subs, posts,etc.), time, spoiler and NSFW status, and with sorting types (New, Top etc.). The search results could occupy the whole space.

Additional context
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[AbsurdlySuspicious]

I'll rename it as general search issue if you dont mind. Design descisions is completely different matter, let's discuss it when general search and filtering functionality is done

[AbsurdlySuspicious]

Related to #478, this one should probably go first in any case