Quagga: Implement VRF change semantics for an interface

Quagga: Implement VRF change semantics for an interface

Implement VRF change semantics for an interface to be invoked
when an interface is moved from one VRF (e.g., the Default) to
another. This includes the message definition as well as updating,
deleting or adding the interface from clients, depending on their
interest in the VRFs (old and new). Also handle replay of the
addresses on the interface upon VRF change, if required.

Signed-off-by: Vivek Venkatraman <vivek@cumulusnetworks.com>
Reviewed-by:   Donald Sharp <sharpd@cumulusnetworks.com>
Reviewed-by:   Don Slice <dslice@cumulusnetworks.com>
Ticket: CM-9527
Reviewed By: CCR-4174
Testing Done: Manual tests of various scenarios