Move mediaprovider_app to common code

The policy under device folder will be removed for GSI, so move the
policy to common code.

Bug: 196326750
Test: build pass
Change-Id: I9544db1771ba7b94a98913bf892386f95cf919be
Merged-In: I9544db1771ba7b94a98913bf892386f95cf919be
1 file changed