Issue Description: 

The DataPlane only emits metrics relating to HTTP requests made to the ControlPlane. As part of the preliminary work for "Observability" we need to emit a metric allowing us to monitor the time taken to provision a ManagedBridge and/or ManagedProcessor. This can be used as a basic metric to trace through into Pager Duty/Grafana etc.

Acceptance Criteria:

Metrics are created representing the time taken to provision a resource.

Out of Scope:

Observability configuration. This is purely DataPlane code changes.