Provide a starter pack of grafana dashboard definitions to make it easier to get started monitoring posit team

[statik]

@atheriel and I interviewed a customer who shared that they had 30K lines of grafana dashboard definitions in json and cloudformation.

This ticket is for providing some useful grafana dashboard definitions as a starting point so it's less of a lift for customers to get started with monitoring posit team.

I will do a bit of research to try and get a list of metrics to include.

[stevenolen]

relates to #47 and #77