[FROG] Announcing PBR for FRR

[Donald Sharp]

All -

I'd like to announce the availability of a new daemon for FRR on the
master branch. PBR( Policy Based Routing ) allows operators to setup
policy maps that allow special control forwarding.  To configure PBR,
see `doc/user/pbr.rst`.  Here is a quick example of how to configure:

nexthop-group EVA
  nexthop 4.3.2.1 swp5
  nexthop 6.4.3.2
!

pbr-map DONNA seq 10
  match src-ip 192.168.210.0/24
  match dst-ip 192.168.140.0/24
  set nexthop-group EVA
!

int swp54
  pbr-policy DONNA
!

This configuration says, on the incoming interface swp54 if the src
matches 192.168.210.0/24 and the dest matches 192.168.140.0/24, use
nexthop-group EVA for forwarding the packet.

I'd like to thank Vivek, Don, Quentin, Philippe and Russ for their
hard work on getting this code into FRR.

thanks!

donald