chore: add grafana for monitoring

.env.example

···
+ENVIRONMENT=prod # can be "dev" as well
 RELAY_LENIENT_SYNC_VALIDATION=true
 RELAY_REPLAY_WINDOW=48h
 RELAY_PERSIST_DIR=/data/relay/persist

conf/Caddyfile

···
     }
 
     reverse_proxy localhost:2470
+    reverse_proxy localhost:3000
 }

conf/grafana.ini

···
+[security]
+
+admin_user = admin
+admin_password = password1 # CHANGE THIS IF USING GRAFANA

docker-compose.yml

···
     volumes:
         - $PWD/conf:/etc/caddy
         - caddy_data:/data
+  # Uncomment grafana and prometheus before building container if you want to use these
+  # grafana:
+  #   env_file: .env
+  #   image: grafana/grafana-oss
+  #   container_name: grafana
+  #   restart: unless-stopped
+  #   depends_on:
+  #     - prometheus
+  #   ports:
+  #     - "3000:3000"
+  #   networks:
+  #      - backend
+  #   volumes:
+  #     - ./conf/grafana.ini:/etc/grafana/grafana.ini
+  #     - ${HOME}/grafana-storage:/var/lib/grafana
+  # prometheus:
+  #   image: prom/prometheus:latest
+  #   networks:
+  #      - backend
+  #   ports:
+  #     - "9090:9090"
+  #   volumes:
+  #     - ./prometheus.yml:/etc/prometheus/prometheus.yml:ro
+  #   depends_on:
+  #     - relay
   db:
     env_file: .env
     image: postgres:16-alpine
···
 volumes:
   caddy_data:
   caddy_config:
+  grafana-storage: {}
 
 networks:
   backend:

prometheus.yml

···
+scrape_configs:
+  - job_name: "relay"
+    static_configs:
+      - targets: ["relay:2471"]