Abstracting out all the Laucher related logic

> Enabling swipe up geture for fallback activity
> Using a preferecens for showing back button

Bug: 75979063
Change-Id: I8bbb44d8e250428c3da9bde57975dc4f952624be
diff --git a/quickstep/AndroidManifest.xml b/quickstep/AndroidManifest.xml
index 4a26494..8b28597 100644
--- a/quickstep/AndroidManifest.xml
+++ b/quickstep/AndroidManifest.xml
@@ -47,7 +47,8 @@
         <!-- STOPSHIP: Change exported to false once all the integration is complete.
         It is set to true so that the activity can be started from command line -->
         <activity android:name="com.android.quickstep.RecentsActivity"
-            android:exported="true" />
+            android:exported="true"
+            android:excludeFromRecents="true" />
 
         <!-- Content provider to settings search -->
         <provider