Merge pull request #3486 from freifunk-gluon/backport-3477-to-v2023.2.x

[Backport v2023.2.x] gluon-ebtables-filter-multicast: block packets with Gluon VXLAN multicast destination

package/gluon-ebtables-filter-multicast/luasrc/lib/gluon/ebtables/355-mcast-drop

 rule ('MULTICAST_OUT -p IPv6 --ip6-dst ff02::1/128 -j DROP')
+rule ('MULTICAST_OUT -p IPv6 --ip6-dst ff02::15c/128 -j DROP') -- Gluon VXLAN multicast group
 rule ('MULTICAST_OUT -p IPv6 --ip6-dst ff00::/8 -j mark --set-mark 0x4 --mark-target RETURN')
 rule ('MULTICAST_OUT -j DROP')