Missing internal network on apache example compose file

Nobody has claimed this yet.

The current docker-compose.yml inside the .example/apache folder is missing an internal network to allow the app service to connect to the db service.

This is my current working docker-compose file:

```yml
version: "3"

services:
db:
image: mariadb:10.11
command: --max-allowed-packet=64MB
restart: always
volumes:
- db:/var/lib/mysql:Z
env_file:
- ./db.env
networks:
- matomo-network

app:
container_name: matomo
image: matomo
restart: always
volumes:
# - ./config:/var/www/html/config:z
# - ./logs:/var/www/html/logs:z
- matomo:/var/www/html:z
environment:
- MATOMO_DATABASE_HOST=db
env_file:
- ./db.env
expose:
- 80
networks:
- matomo-network
- reverse-proxy-network

volumes:
db:
matomo:

networks:
matomo-network:
reverse-proxy-network:
external: true

```

Open .example/apache/docker-compose.yml and compare its service network configuration with the working Compose example in the issue. Verify that the app and db services can communicate over the intended internal network, while preserving the existing reverse-proxy setup. Done means the example file contains the required network configuration for app-to-db connectivity.

Written by the indexing model from the issue text.