Major refactor and updated metrics

Dashboard changed a lot!
JSON definition can be downloaded here or on https://grafana.com/api/dashboards/3681/revisions/2/download

Added

• Support for showing multiple instances of
• Table with generic overview of all observed Prometheus instances and their status
• All missing metric added or changed since the last release

Initial release

First release

• added dashboard definition
• added github pages with docs
• published dashboard on grafana.com see https://grafana.com/dashboards/3681