Android: Implement DocumentProvider

This allows users to access the Dolphin user directory.

Source/Android/app/src/main/res/values-v24/bools.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <bool name="enableDocumentProvider">true</bool>
+</resources>

Source/Android/app/src/main/res/values/bools.xml

@@ -1,4 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
     <bool name="hasTouch">true</bool>
+    <bool name="enableDocumentProvider">false</bool>
 </resources>