docker: add an extra listener for localhost

Make sure the lncli command can be used inside of the container without
needing to specify the --rpcserver flag all the time. Issue: #4937

docker/lnd/start-lnd.sh

@@ -65,5 +65,6 @@ exec lnd \
     "--$BACKEND.rpcuser"="$RPCUSER" \
     "--$BACKEND.rpcpass"="$RPCPASS" \
     "--rpclisten=$HOSTNAME:10009" \
+    "--rpclisten=localhost:10009" \
     --debuglevel="$DEBUG" \
     "$@"