Enhance incognito mode (#4073)

* When in Incognito Mode don't set lastUsedSource

* When in Incognito Mode don't save chapter progress

Still allows tracking and mark as read when reaching last page

* When in Incognito Mode don't mark as read (overwritten if hasTrackers)

app/src/main/java/eu/kanade/tachiyomi/ui/browse/source/SourceController.kt

@@ -194,7 +194,9 @@ class SourceController :
      * Opens a catalogue with the given controller.
      */
     private fun openSource(source: CatalogueSource, controller: BrowseSourceController) {
-        preferences.lastUsedSource().set(source.id)
+        if (!preferences.incognitoMode().get()) {
+            preferences.lastUsedSource().set(source.id)
+        }
         parentController!!.router.pushController(controller.withFadeTransaction())
     }