Improve metric for active application and workloads

[thisthat]

Technical Details

The current implementation reports active deployments and apps via synchronous instruments with deltas.
This implementation has some drawbacks because items are removed from being active only when they have finished and an end time is set. If an external entity removes the CRDs, e.g., via kubectl delete, the value reported is out of sync with the real value.

Action item

Change the implementation to make use of async instrument via Gauges: https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/api.md#asynchronous-gauge-creation

DoD

• Metrics for active deployments are stable