Add snapshotProfile APIs to installd

Add APIs that will snapshot the profile information of packages
in a well known location.

The snapshot ownership is given to AID_SYSTEM. The location is
next to the application reference profile:
/data/misc/profiles/ref/pkg_name/primary.prof.snapshot.

The intended flow for snapshotting profiles is:
mInstaller.snapshotProfile(appId, packageName, codePath);
// open profile snapshot
mInstaller.destroyProfileSnapshot(packageName, codePath);

The reference profile directory is made searchable by others
(in order for the system to be able to open the snapshot profile).

Test: installd_dexopt_test installd_utils_test
Bug: 30934496
Change-Id: Ic4973d5c67243d7724ecd24a238ed0ae8baadcc6