Added support for multicast vxlan tunnels which are used for bridge domain flooding instead
of flooding the all unicast tunnels in the bridge domain.
features added:
* conditional flooding to some of the BD members - based on existance of multicast tunnel member
* added local multicast adjacency - multicast packets are handled as the same as unicast - based on src (unicast) address
* refactored some of vxlan tunnel creation code - to unify ip4/6 handling
Change-Id: I60cca4124265a8dd4f6b2d6ea8701e52e7c1baa4
Signed-off-by: Eyal Bari <ebari@cisco.com>