net: sockets: IPv6_MULTICAST_LOOP Support

Add support for the IPV6_MULTICAST_LOOP socket option.
This option allows enabling or disabling the consumption of multicast
packets by the sender. By default, the socket option will be enabled.

Co-authored-by: Pieter De Gendt <pieter.degendt@gmail.com>

Signed-off-by: Sayooj K Karun <sayooj@aerlync.com>