#3520 Searchable Settings (#3683)

* Adding class stubs for settings search, UI elements.

* -  implement searchable settings
- `SettingsController.setupPreferenceScreen` must return a PreferenceScreen

* Remove unneeded SettingsControllerFactory.

* Set query hint, clean up code smell.

* Add search button to MoreController, stop infinite recursion.

* - initialize SearchResultCollection once in Activity.onCreate

* - implement prefernce highlighting after settings search

* - Ensure all Preferences have a key set or else the highlighting effect will have no effect on it.
- remove ExtensionFilterController and SourceFilterController from settingControllersList in SettingsSearchHelper, since those are related to Extensions and not Settings

* Limiting search to settings menu only, localized breadcrumb string, and code cleanup after code review.

* - moved call to SettingsSearchHelper.initPreferenceSearchResultCollection() into SettingsSearchController

* Code review cleanup and refactoring.

* Inlined non-reused key strings.

* Adding more UI polish, add comments for future enhancements.

* - retain search query when navigating *away* from SettingsSearchController
- keep `searchItem` in `expandActionView` state until user goes back (fixes the empty view in `SettingsSearchSearchController` issue)

Co-authored-by: mpm11011 <markuscicero5@gmail.com>
Co-authored-by: lmj0011 <9396189+lmj0011@users.noreply.github.com>
(cherry picked from commit 766f9e37b5)

# Conflicts:
#	app/build.gradle
#	app/src/main/java/eu/kanade/tachiyomi/ui/browse/source/SourceFilterController.kt
#	app/src/main/java/eu/kanade/tachiyomi/ui/more/AboutController.kt
#	app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsAdvancedController.kt
#	app/src/main/java/eu/kanade/tachiyomi/ui/setting/SettingsLibraryController.kt

app/src/main/java/exh/debug/SettingsDebugController.kt

@@ -20,7 +20,7 @@ import kotlin.reflect.full.declaredFunctions
 
 class SettingsDebugController : SettingsController() {
     @SuppressLint("SetTextI18n")
-    override fun setupPreferenceScreen(screen: PreferenceScreen) = with(screen) {
+    override fun setupPreferenceScreen(screen: PreferenceScreen) = screen.apply {
         title = "DEBUG MENU"
 
         preferenceCategory {