Merge a number of changes required to hook up OpenBSM 1.2-alpha2's

Merge a number of changes required to hook up OpenBSM 1.2-alpha2's
auditdistd (distributed audit daemon) to the build:

- Manual cross references
- Makefile for auditdistd
- rc.d script, rc.conf entrie
- New group and user for auditdistd; associated aliases, etc.

The audit trail distribution daemon provides reliable,
cryptographically protected (and sandboxed) delivery of audit tails
from live clients to audit server hosts in order to both allow
centralised analysis, and improve resilience in the event of client
compromises: clients are not permitted to change trail contents
after submission.

Submitted by:	pjd
Sponsored by:	The FreeBSD Foundation (auditdistd)