bgpd: evpn pip handle svi ip route

bgpd: evpn pip handle svi ip route

By default announct Self Type-2 routes with
system IP as nexthop and system MAC as
nexthop.

An API to check type-2 is self route via
checking ipv4/ipv6 address from connected interfaces list.

An API to extract RMAC and nexthop for type-2
routes based on advertise-svi-ip knob is enabled.

When advertise-pip is enabled/disabled, trigger type-2
route update. For self type-2 routes to use
anycast or individual (rmac, nexthop) addresses.

Ticket:CM-26190
Reviewed By:
Testing Done:

Enable 'advertise-svi-ip' knob in bgp default instance.
the vrf instance svi ip is advertised with nexthop
as default instance router-id and RMAC as system MAC.

Signed-off-by: Chirag Shah <chirag@cumulusnetworks.com>