add openmetric/prometheus support for monitoring

[Grummfy]

Hello, at fosdem I suggest some idea about the monitoring part, we suggest I create an issue for it, so here we are.

In the dashboard we have a part for a monitoring on the deployment. My suggestion is double:

• add information from the metrics blackbox exporter do (see https://github.com/prometheus/blackbox_exporter ). It's a part of prometheus monitoring to observe website health. The format is the one used by prometheus : https://openmetrics.io/ it could help to go deeper
• add monitoring in the same format for the health of this itself

thanks

[eddiejaoude]

Great to meet you at Fosdem @Grummfy . Thank you for sharing and logging the idea 👍