Add entry for Grafana "Autonity metrics dashboard once open sourced

[cmjc]

Platform is working on developing the https://grafana.com/grafana/dashboards/13877-single-geth-dashboard/ to be Autonity specific and then publishing it for the community.

When this is done, this can be added to the list of community resources.

@raj-shekhar1 @dweng0 following on from our slack this AM, I've created an issue for this

[spenot09]

Hiya, is this issue still relevant or can it be closed in prep for public release?