igmpproxy: allow 0.0.0.0/0 as allowed net in the config

Signed-off-by: Felix Fietkau <nbd@openwrt.org>

git-svn-id: svn://svn.openwrt.org/openwrt/packages@40729 3c298f89-4303-0410-b956-a3cf2f4a3e73
igmpproxy: move to trunk, add myself as maintainer

git-svn-id: svn://svn.openwrt.org/openwrt/packages@40730 3c298f89-4303-0410-b956-a3cf2f4a3e73