Move MQTT out of the main compose for testing server and client disconnects

mqtt-compose.yml

@@ -0,0 +1,19 @@
+services:
+# The Post Office (MQTT Broker)
+  mqtt-broker:
+    image: eclipse-mosquitto:latest
+    container_name: radio-mqtt
+    restart: always
+    ports:
+      - "1883:1883"
+      - "9001:9001"
+    volumes:
+      - ./mosquitto/config/:/mosquitto/config/
+      - ./mosquitto/data/:/mosquitto/data/
+      - ./mosquitto/log/:/mosquitto/log/
+    networks:
+      - radio-shared-net
+
+networks:
+  radio-shared-net:
+    external: true