Detection of labels

User story
As a user, I don't want to provide information that can be detected from the service.

Details

At the moment users have to provide standard labels manually, so it requires the user's knowledge of those labels. We already have a few dashboards and a few features that rely on labels. So it's better to detect it the moment the user adds a service.

List of labels that could be detected:

• cluster
• replication_set
• service_role?

https://confluence.percona.com/display/PMM/Unified+labels+across+Query+Analytics+and+Prometheus