Introduce a manifest flag for auto-revoke exemption request

The implementation will filter apps eligible to receive exemption from
permission auto-revoke to just the apps that declare feature usage.

Having the manifest declaration is important for us to be able to
implement a whitelist policy.

Bug: 146513245
Test: lint/presubmit
Change-Id: I87652c276568bf2dd1c48f7cacebbc930334a7c4