Remove $FreeBSD$: two-line nroff pattern

Remove /^\.\\"\n\.\\"\s*\$FreeBSD\$$\n/

add valectl to the system commands

The valectl(4) program is used to manage vale(4) switches.
Add it to the system commands so that it can be used right away.
This program was previously called vale-ctl, and stored in
tools/tools/netmap

Reviewed by: hrs, bcr, lwhsu, kevans
MFC after: 1 week
Differential Revision: https://reviews.freebsd.org/D22146

netmap: add load balancer program

Add the lb program, which is able to load-balance input traffic
received from a netmap port over M groups, with N netmap pipes in
each group. Each received packet is forwarded to one of the pipes
chosen from each group (using an L3/L4 connection-consistent hash function).
This also adds a man page for lb and some cross-references in related
man pages.

Reviewed by: bcr, 0mp
Approved by: gnn (mentor)
Differential Revision: https://reviews.freebsd.org/D17735