updated policy to replace cockpit policy in selinux-policy package

Reviewed-by: Stef Walter <stefw@redhat.com>
selinux: Move selinux policy into its own directory

This is so we can more effectively track changes to the policy
with downstream distro.
selinux: Some minor fixes after changes from Dan

 * Remove duplicate interface definitions
 * Temporarily listen on a broader port until the
   corenet_tcp_bind_cockpit_port() gets into f20
 * Add auth_write_login_records so cockpit-session can
   write to wtmp

Closes #611

Reviewed-by: Dan Walsh <dwalsh@redhat.com>