Allow privapp permission allowlist in apex

Read priv-app permission allowlists from APEX file and warn if
they're in the /system partition instead.

Test: boots
Bug: 190375768
Change-Id: I37d6deb60f0dffb75dd634075cd95bcf7ddf9684
Merged-In: I37d6deb60f0dffb75dd634075cd95bcf7ddf9684
3 files changed