fix: docker compose network config so that containers may communicate

MQTT from gateway stack and app must be on the same network
It was implied when they were from the same stack, but when splitting
docker creates two default separated networks
This commit creates a network for MQTT and makes the app join it

Works only if the two stacks are on the same host (which is the case
during development)

app/docker-compose.yml

@@ -2,3 +2,9 @@ services:
   consumer:
     build: ./consumer
     restart: unless-stopped
+    networks:
+      - lora-gateway_mqtt
+
+networks:
+  lora-gateway_mqtt:
+    external: true

lora-gateway/docker-compose.yml

@@ -3,6 +3,10 @@ services:
     image: chirpstack/chirpstack:4
     command: -c /etc/chirpstack
     restart: unless-stopped
+    ports:
+      - "8080:8080"
+    networks:
+      - internal
     volumes:
       - ./configuration/chirpstack:/etc/chirpstack
     depends_on:
@@ -13,14 +17,14 @@ services:
       - MQTT_BROKER_HOST=mosquitto
       - REDIS_HOST=redis
       - POSTGRESQL_HOST=postgres
-    ports:
-      - "8080:8080"
 
   chirpstack-gateway-bridge:
     image: chirpstack/chirpstack-gateway-bridge:4
     restart: unless-stopped
     ports:
       - "1700:1700/udp"
+    networks:
+      - internal
     volumes:
       - ./configuration/chirpstack-gateway-bridge:/etc/chirpstack-gateway-bridge
     environment:
@@ -36,6 +40,8 @@ services:
     command: -c /etc/chirpstack-gateway-bridge/chirpstack-gateway-bridge-basicstation-eu868.toml
     ports:
       - "3001:3001"
+    networks:
+      - internal
     volumes:
       - ./configuration/chirpstack-gateway-bridge:/etc/chirpstack-gateway-bridge
     depends_on:
@@ -47,6 +53,8 @@ services:
     command: --server chirpstack:8080 --bind 0.0.0.0:8090 --insecure
     ports:
       - "8090:8090"
+    networks:
+      - internal
     depends_on:
       - chirpstack
 
@@ -56,6 +64,8 @@ services:
     volumes:
       - ./configuration/postgresql/initdb:/docker-entrypoint-initdb.d
       - db:/var/lib/postgresql
+    networks:
+      - internal
     environment:
       - POSTGRES_USER=chirpstack
       - POSTGRES_PASSWORD=chirpstack
@@ -67,6 +77,8 @@ services:
     command: redis-server --save 300 1 --save 60 100 --appendonly no
     volumes:
       - redis:/data
+    networks:
+      - internal
 
   mosquitto:
     image: eclipse-mosquitto:2
@@ -75,7 +87,14 @@ services:
       - "1883:1883"
     volumes: 
       - ./configuration/mosquitto/config/:/mosquitto/config/
+    networks:
+      - internal
+      - mqtt
 
 volumes:
   db:
   redis:
+
+networks: 
+  internal:
+  mqtt: