Add option to drop "client" from the metrics endpoint

[czenker]

Please describe your use case / problem.
The metrics endpoint exposes the connect_active_status and connect_count metrics with a client label. This label contains the user identification and hostname of the connecting user. In my case it is something like christian@xopn-laptop. This is almost always personal data as mentioned in GDPR. Gathering data like that in a time series database is potentially problematic, as it might allow to track working times of an individual.

Describe the solution you'd like
Having an option to turn of tracking of the client in the metrics would be a perfect solution in my opinion. The install_id is a good enough pseudonym to identify "clients" without exposing an individual.

Describe alternatives you've considered
The label client can be dropped in Prometheus' configuration. This works well enough as a workaround.
But the data is still visible in the metrics endpoint and having a documented option increases the possibility an admin chooses a configuration that follows their local laws or company guidelines.

Versions (please complete the following information)

• ambassador-telepresence-manager: 2.18.1