Update the monitoring documentation

[nwneisen]

The current documentation for monitoring is very limited. We should add some things such as

• How to access the grafana and prometheus dashboards without using proxy pass
• What the password for grafana is or how to find it
• An example of how a user might use either addon

[KoryKessel-Mirantis]

@nwneisen, please submit a raw PR that covers this Issue that will start the whole integrate-to-great process.

[nwneisen]

@KoryKessel-Mirantis I'll have to look up who did the monitoring work. This was just a ticket I opened to point out that we are missing docs