VAULT-1564 report in-flight requests (#13024)

* 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

command/server/config_test_helpers.go

@@ -701,6 +701,7 @@ func testConfig_Sanitized(t *testing.T) {
 		"enable_ui":                           true,
 		"enable_response_header_hostname":     false,
 		"enable_response_header_raft_node_id": false,
+		"log_requests_level":                   "basic",
 		"ha_storage": map[string]interface{}{
 			"cluster_addr":       "top_level_cluster_addr",
 			"disable_clustering": true,