Update grafana tutorial to point to more resources

[nuke-web3]

https://github.com/paritytech/substrate/tree/master/.maintain/monitoring/grafana-dashboards

Ideally they'd get autopublished on the official Grafana repository or something, but the effort of doing that is probably not worth the gain

---

https://github.com/wpank/polkadot-local-network/blob/master/docker-compose.yml

---

Add Loki content?