Instrumentation to collect queue metrics for auto scaling

Add instrumentation to necessary components to collect metrics for auto scaling of queue consumers.

Some metrics may not be centralized in that different components collect the same value. Use of meta data allows the monitoring system to combine these into a single value for each collection period.

All metrics follow the naming convention as outlined in devdoc/Metrics.rst. For all metrics required below, the scope is hpcc.

Metrics:

name: hpcc.queue_items.length
type:  gauge
units: SMeasureCount
desc: Current count of items waiting in the queue to be processed.

name: hpcc.queue_items.in_flight
type: gauge
units: SMeasureCount
desc: Current count of items being processed.

name: hpcc.queue.blocked_waiting
type: gauge
units: SMeasureCount
desc: Current number of processes blocked waiting for a queue item to process.

All metrics shall include meta data for the queue name. The meta data key shall be queue_name