A new log reports on the "session workflow" loop time if time taken exceeds the existing slowMs config. The session workflow includes all of the work captured by the slow query log, and more. We capture how long it took to:
1) Receive a message
2) Process that message into a work item (effectively a command)
3) Do the work (effectively the same time frame as slow query)
4) Send the response
5) Do any cleanup after sending a response

We log if the time from steps 2-5 was slow (step 1 is not an indication of slowness because we are waiting for a client to send us a message).

Note: this does not do sampling like the slow query log.

Description of Linked Ticket

Context: SERVER-55638 and SERVER-63883 were both logged before our rework to SessionWorkflow started. They are both being closed in favor of an approach that consolidates the two implementations and allows for us to spend some time clarifying requirements with bruce.lucas@mongodb.com.

Previous task: (SERVER-69830) ** At each stage of the SessionWorkflow, capture `timeSpent` and store it in an object associated 1:1 with each loop.

This task: Report on these gathered metrics in a manner that's satisfactory to the requirements of stakeholders of the original tickets: SERVER-55638 and SERVER-63883.

Requirements should be discussed with bruce.lucas@mongodb.com.