[EPIC] Create Plutono plugin

[artherd42]

Context

A platform like Greenhouse should have a tool for visualising dashboards. Currently Plutono is used as a solution, a fork of Grafana 7.5.17 under the Apache 2.0 licence, limited to maintenance and security updates.

Tasks

• ([plutono] Initialise the plugin with basic functionality  #273)

[richardtief]

The Grafana community helm chart has been transferred to Plutono. Checked out at appVersion: 7.5.3 as it is the last source before Grafana v8.