feat: new prometheus and nodes dashboards

[trnl]

What

• Add two new dashboards. One for Prometheus self-monitoring. Another one for Nodes overview.

Screenshot

[trnl]

@alexgarel, this is the first PR here, and there is no CONTRIBUTING.md. Please let me know if I'm following the policies right.

[alexgarel]

@trnl yes it's alright.

I will blindly merge your proposal as it's really hard to read config files like that. (really cool that you have included screenshots BTW).

I'm not sure about this way of managing dashboard through git, if you have a better proposal, feel free to open an issue !

[trnl]

Managing in git is the best way! You have fully immutable grafana instance. E.g. people experimenting with dashboards on the instance, but if they finished - they submit a PR. It is very easy to see the changes and also cleanup the instance of 'experiments' - just restart the docker container.

[alexgarel]

Oh, I did not realize that the changes were there until docker removal / recreation.

That said, it means you should avoid doing too much dashboard in parallel.

@trnl ain't there a way to have a specific section (project ?) which would be stateful (and not in git) just for experiments ?