In addition, this commit also heavily changes the structure of the
generic "video card" item. Main benefits:
* Improved accessibility for keyboard users
* Many styling glitches were fixed
* PlaylistVideos now use the same items as the rest
* Elements all have distinct CSS classes
* Design can be expanded to add more icons
* on watch page and video cards (search results, playlists, etc...)
* on /feed/playlists
* in search filters (not normalized in order to avoid collisions with
an existing PR that reworks the search filters)
* Extract feed routes from invidious.cr
* Removes the deprecated route for /feed/top
* Deprecate /view_all_playlist & use /feed/playlists
* Move feed views into their own directory
* Add haltf method to halt current route context
* Change status_code + return blocks to use haltf
* Set appropriate response headers for RSS routes
