InstalledApp: show link to Google Play

Shows a Google Play store icon in the App Info actionbar of apps
Excludes aosp built ones, but still works for apps generally found in /system, like SuperSU
The openPlayStore() code was created by @nicholaschum for Substratum, thank you!

BenzoEdit: fixed it for pie and updated drawable
Change-Id: Ic55e572405d97b1f8ae3f8e3b5aceaa38b6a991e
Signed-off-by: mydongistiny <jaysonedson@gmail.com>
diff --git a/res/values/custom_strings.xml b/res/values/custom_strings.xml
index 3978f3c..97eefc0 100644
--- a/res/values/custom_strings.xml
+++ b/res/values/custom_strings.xml
@@ -25,4 +25,8 @@
     <string name="show_light_on_zen_title">Blink during Do Not Disturb</string>
 
     <string name="select_sim_for_sms">Select a SIM for SMS</string>
+
+    <!-- App details: open play store link if app is user installed -->
+    <string name="app_play_store">Google Play</string>
+
 </resources>