neverallow_macros

Recovery should never be accessing files from /data.
In particular, /data may be encrypted, and the files within
/data will be inaccessible to recovery, because recovery doesn't
know the decryption key.

Enforce write/execute restrictions on recovery. We can't tighten
it up further because domain.te contains some /data read-only
access rules, which shouldn't apply to recovery but do.

Create neverallow_macros, used for storing permission macros
useful for neverallow rules. Standardize recovery.te and
property_data_file on the new macros.

Change-Id: I02346ab924fe2fdb2edc7659cb68c4f8dffa1e88