New dashboard for av equipment per room

[zeridon]

As coordinator it would be usefull if there is a dashboad in grafana for av equipment.

The main idea is to have a high level of overview if required HW is deployed as needed

We have the inventory system as source of truth (as AV gear/hw needs to be checked in there) and it has multiple states.

The vision is that green means gear is deployed, orange yellow if something is missing, red if nothing is there.

It seems most logical to have a sql exporter in liew of select count(*) from gear where room_name=$VAR with value mapping as follows

• 0 = red
• > 0 = yellow
• >2 = green

[markvdb]

Ties into #142