feeds: add freifunk feed

Read the freifunk packages, that have been moved from the LuCI feed
into its own feed in January 2019.

Signed-off-by: Sven Roederer <freifunk@it-solutions.geroedel.de>

feeds.conf.default

@@ -2,6 +2,7 @@ src-git packages https://git.openwrt.org/feed/packages.git
 src-git luci https://git.openwrt.org/project/luci.git
 src-git routing https://git.openwrt.org/feed/routing.git
 src-git telephony https://git.openwrt.org/feed/telephony.git
+src-git freifunk https://github.com/freifunk/openwrt-packages.git
 #src-git video https://github.com/openwrt/video.git
 #src-git targets https://github.com/openwrt/targets.git
 #src-git management https://github.com/openwrt-management/packages.git