Routing VRF, bugfixes and updates

Feature: Routing VRF
Update: ICMP Redirect support
Update: Data VRF support in NAS-l3
Update: Program loopback address in NPU
Update: Added support for virtual routing IP configuration to configure peer's link local address in hardware.
Bugfix: Update the mgmt route status when the default route with eth0 is getting replaced with default route with null interface.

Signed-off-by: Garrick He garrick_he@dell.com

open-switch / opx-nas-l3