Add enforcement of idmap policies

Teaches idmap2 to recognize policy restrictions put on overlayable
resources. If overlayable enforcement is turned on for an overlay, then
any resources defined within the overlayable api of the target will have
policy restrictions imposed on them. All resources without overlayable
definitions will continue to be overlayable without policy restrictions.

Bug: 119390857
Test: atest idmap2 and booting

Co-authored-by: Ryan Mitchell <rtmitchell@google.com>
Change-Id: I7e435648eb6e4a87b0b90a7b2a0c3f33c1516ea6