Clean up, unify, and deduplicate app domain rules.

Coalesce a number of allow rules replicated among multiple
app domains.

Get rid of duplicated rules already covered by domain, appdomain,
or platformappdomain rules.

Split the platformappdomain rules to their own platformappdomain.te
file, document them more fully, and note the inheritance in each
of the relevant *_app.te files.

Generalize isolated app unix_stream_socket rules to all app domains
to resolve denials such as:

avc:  denied  { read write } for  pid=11897 comm="Binder_2" path="socket:[203881]" dev="sockfs" ino=203881 scontext=u:r:release_app:s0 tcontext=u:r:untrusted_app:s0 tclass=unix_stream_socket

avc:  denied  { getattr } for  pid=11990 comm=4173796E635461736B202334 path="socket:[203881]" dev="sockfs" ino=203881 scontext=u:r:release_app:s0 tcontext=u:r:untrusted_app:s0 tclass=unix_stream_socket

avc:  denied  { getopt } for  pid=11990 comm=4173796E635461736B202334 scontext=u:r:release_app:s0 tcontext=u:r:untrusted_app:s0 tclass=unix_stream_socket

avc:  denied  { read write } for  pid=6890 comm="Binder_10" path="socket:[205010]" dev="sockfs" ino=205010 scontext=u:r:release_app:s0 tcontext=u:r:media_app:s0 tclass=unix_stream_socket

avc:  denied  { getattr } for  pid=11990 comm=4173796E635461736B202334 path="socket:[205010]" dev="sockfs" ino=205010 scontext=u:r:release_app:s0 tcontext=u:r:media_app:s0 tclass=unix_stream_socket

avc:  denied  { getopt } for  pid=11990 comm=4173796E635461736B202334 scontext=u:r:release_app:s0 tcontext=u:r:media_app:s0 tclass=unix_stream_socket

Change-Id: I770d7d51d498b15447219083739153265d951fe5
Signed-off-by: Stephen Smalley <sds@tycho.nsa.gov>