Add Grafana

[brettimus]

TODO

• Spin up Grafana with docker compose as well
• Add the autometrics charts to grafana container
• Document how to import the charts
• Backlink to the autometrics-shared repo

OPTIONAL

• Make the autometrics charts show up in grafana automatically

[brettimus]

Not sure if we can import the autometrics dashboard JSON automagically into the container (so users don't have to manually import them)

If I can't get that to work, I'll document how to import the charts

[brettimus]

couldn't get autoloading to work, so settled on just documenting how to import (could maybe use a screenshot too)

tracking autoloading in this issue: #4