* VAULT-1564 report in-flight requests
* adding a changelog
* Changing some variable names and fixing comments
* minor style change
* adding unauthenticated support for in-flight-req
* adding documentation for the listener.profiling stanza
* adding an atomic counter for the inflight requests
addressing comments
* addressing comments
* logging completed requests
* fixing a test
* providing log_requests_info as a config option to determine at which level requests should be logged
* removing a member and a method from the StatusHeaderResponseWriter struct
* adding api docks
* revert changes in NewHTTPResponseWriter
* Fix logging invalid log_requests_info value
* Addressing comments
* Fixing a test
* use an tomic value for logRequestsInfo, and moving the CreateClientID function to Core
* fixing go.sum
* minor refactoring
* protecting InFlightRequests from data race
* another try on fixing a data race
* another try to fix a data race
* addressing comments
* fixing couple of tests
* changing log_requests_info to log_requests_level
* minor style change
* fixing a test
* removing the lock in InFlightRequests
* use single-argument form for interface assertion
* adding doc for the new configuration paramter
* adding the new doc to the nav data file
* minor fix