Add profile for samba-bgqd

... and some rules in the smbd profile to execute it and send it a term signal.

samba-bgqd is (quoting its manpage) "an internal helper program performing asynchronous printing-related jobs."

samba-bgqd was added in Samba 4.15.

Fixes: https://bugzilla.opensuse.org/show_bug.cgi?id=1191532

I propose this patch for 3.0 and master.