search: Overhaul location dialog, fix accessibility and keynav

Fixes a few things missed in my initial MR for this panel:

  • I re-designed the Search Locations dialog, dropping the tabs in favor of AdwPreferences{Window,Page,Group}
  • Fixed keyboard navigation for the search results listbox
  • Set proper accessibility relations
  • Used AdwActionRow for search location rows, and made clicking the search results rows activate their switches

Merge request reports