luci-proto-3g: make it a self-contained package
The follow error will appear after clicking "Switch protcol" to 3g when
luci-proto-3g was not installed. Fix this by moving the relevant parts
from luci-proto-ppp into luci-proto-3g and making it complete as a
single protocol handler
> Missing protocol extension for proto "3g"
> cannot open /usr/lib/lua/luci/model/cbi/admin_network/proto_3g.lua: No such file or directory
Closes openwrt/luci#1815
Signed-off-by: Florian Eckert <fe@dev.tdt.de>
Signed-off-by: Yousong Zhou <yszhou4tech@gmail.com>