Predefined selection for labes in maintenance templates

[christopherhans]

The fact that Prometheus labels are case sensitive leads to user operating errors. I.e. region='NA-US-1' instead of region='na-us-1'.
If the options for those labels would be predefined (i.e. dropdown menu), we would prevent wrong user input.
For labels with a limited range of options, like region, it could be a hard coded list, because i.e. the regions are more or less static. For labels, like cluster or hosts, this is probably not an option.
Alternatively you could get the label values directly from Prometheus.

Initially I thought about just transforming every input to lowercase. But obviously labels don't have to be lowercase. So this is not an option.

Example template: VMware maintenance - VCenterRedundancyLostHAPolicyNotConfigured