Counters and Lists: Default Grafana dashboards

[markmandel]

Is your feature request related to a problem? Please describe.
Pulling out from #2716

It's great we have metrics for Counters and Lists, but it would be good to have examples and some default Grafana dashboards!

Describe the solution you'd like
Make some Grafana dashboards that you can install into your metrics dashboards!

Chuck the new dashboard into here: https://github.com/googleforgames/agones/tree/main/build/grafana

Describe alternatives you've considered
Don't do it, but that leaves people to all reinvent the wheel.

Additional context

Once #3649 is merged, metrics will be documented, or you can look at the PR.