Remove duplicated code.

Suggested by:	jmg
The igb(4) driver supports 82580, i350, i354, i210 and i211 chipsets too,
document them.

PR:		192301
MFC after:	1 week
Add support of "/{udp,tcp,proto}" suffix into $firewall_myservices, which
interpreted the listed items as port numbers of TCP services.

A service with no suffix still works and recognized as a TCP service for
backward compatibility.  It should be updated with /tcp suffix.

PR:		194292
MFC after:	1 week
Make the sysctl(8) for checkutf8 positively defined and improve
the description of it.

Submitted by:	Ronald Klop <ronald-lists@klop.ws>
Reviewed by:	rmacklem
Approved by:	rmacklem
Sponsored by:	QNAP Systems Inc.
Add more descriptive metadata to the ISO images.

PR: 		146079
Submitted by: 	Roman Bogorodskiy
MFC after: 	3 days
X-MFC-10.1: 	yes
Sponsored by:	The FreeBSD Foundation