Move metrics inside controller (not global)

At the moment, metrics are global and can be used by just calling `metrics.`. They should ideally be part of the controller package. This will make it easier in the future when we will need to test the controller package, we can easily mock out the metrics provider.

Start by locating the controller package and the current global metrics provider, then trace where metrics. is called. Move the metrics dependency into the controller package so it can be mocked there, and verify that controller behavior and existing metrics usage remain intact.

Written by the indexing model from the issue text.