Petals CDK

Add the following metrics about the threadpool running message exchange processors:

• max size,
• min size,
• max number of allocated threads,
• current number of allocated threads,
• max number of idle threads,
• current number of idle threads,
• number of tasks/requests waiting a thread from the thread pool,
• duration of thread alloactaions (ie, duration of the message exchange processor processing):
  • abolute durations: max, avg, min
  • relative values of a sample: max, avg, min, 10-percentil, 50-percentil, 90-percentile.

A defect will be sent if the current number of allocated threads reachs the max size of the threadpool (ie: no more thread is available)
Another defect will be sent when a tasks/request is waiting a thread from the threadpool (ie: threadpool exhaustion).