Launcher3: Add support for themed icons

[nxc: only apply L3Go changes since we'll use vendor/lawnicons instead]

Author: TheScarastic

go/AndroidManifest-launcher.xml

@@ -65,6 +65,9 @@
             <meta-data
                 android:name="com.android.launcher3.grid.control"
                 android:value="${packageName}.grid_control" />
+            <meta-data
+                android:name="com.android.launcher3.themedicon.option"
+                android:value="${packageName}.grid_control" />
         </activity>
 
     </application>