bgpd: commands to display L3 NHGs and MAC-IP paths linked to an ES

bgpd: commands to display L3 NHGs and MAC-IP paths linked to an ES

Sample output -
===============
torm-11# sh bgp l2vpn evpn es-vrf
ES-VRF Flags: A Active
ESI                            VRF             Flags IPv4-NHG IPv6-NHG Ref
03:44:38:39:ff:ff:01:00:00:01  vrf3            A     1        0        2
03:44:38:39:ff:ff:01:00:00:01  vrf2            A     6        0        4
03:44:38:39:ff:ff:01:00:00:01  vrf1            A     7        0        4
03:44:38:39:ff:ff:01:00:00:02  vrf3            A     2        0        2
03:44:38:39:ff:ff:01:00:00:02  vrf2            A     4        0        4
03:44:38:39:ff:ff:01:00:00:02  vrf1            A     8        0        4

Signed-off-by: Anuradha Karuppiah <anuradhak@cumulusnetworks.com>