Create separate Storage Preferences

Create separate preference xml file for the storage permission, to
ensure other users of "allowed_denied.xml" do not have to manually hide
the storage allowed categories.

Test: Navigate to the app info for an app, select permissions. There
should not be the categories "allowed for media only" and "allowed for
all files".
Fixes: 147808991

Change-Id: Ie1856e3a1dd6df1ba50d373e78a030389db8c392