snackpot.yml, docker-compose.yml - add mopidy and upmpdcli services

mopidy includes icecast

templates/docker-compose/upmpdcli/Dockerfile

@@ -0,0 +1,16 @@
+FROM alpine:3.13
+
+RUN apk update \
+  && apk upgrade \
+  && apk add --no-cache \
+  --repository http://dl-cdn.alpinelinux.org/alpine/edge/testing \
+  python2 \
+  upmpdcli
+
+COPY upmpdcli.conf /etc/upmpdcli.conf
+#RUN adduser -S upmpdcli
+
+EXPOSE 1900/udp
+EXPOSE 49152
+
+ENTRYPOINT ["upmpdcli"]