[apparmor] autogenerated snippets location

[John Johansen]

So we need to settle on a location and name for auto generated snippets
(basically little pieces of policy that are auto generated via a tool)

from my notes of the last meeting where we discussed this we had suggestions
of

  policy-extensions.d
  snippets/autogenerated
  snippets/dhcpd.d
  snippets/foo.d
  snippets/autogenerated/smbd.d

with them living in
  /etc/apparmor.d/local/


at the moment I don't really have a strong preference, but I don't deal
with this end of the tooling much