pkgbase: Put autofs config files in the FreeBSD-autofs package

Reviewed by: emaste
MFC after: 2 weeks
Sponsored by: Beckhoff Automation GmbH & Co. KG
Differential Revision: https://reviews.freebsd.org/D33434

(cherry picked from commit eb14f050a39f7f71110535ad260fb8df5eef068c)