Adding Clear Metric State to UI

[dillu24]

When a metric is problematic, a description will be shown in the problems, where the metric state is stored in Redis. If the user disables a metric so that it no longer alerts him, the erroring state would still be in Redis, and hence in the UI.

Technically, in this case the backend is correct because when it was being monitored, the metric was problematic. However, it could be that the user wants to clear the metric state. Therefore, we could add a button to the UI dashboard which clears a specific metric. Like this we don't have to worry inside the backend about these difficult edge cases.