upmpdcli: Add UPnP icon. Use procd for start/stop. 

Add uci config support for multiple instances

Signed-off-by: Ted Hess <thess@kitschensync.net>
What is the correct way of adding a user? The `USERID` statement in the `Makefile` did not seem to have any effect so I added this in order to address user creation as seen [here](https://github.com/openwrt/packages/blob/1fe4160fc29ed7d4a95fcd47452ee1c2223d5f1b/net/bind/files/named.init#L29-L30) and in several other packages.