Fix #3404 bulk all improvements (#3405)

* Add more explicit support for what to do when dropped documents are encountered. Now defaults to halting the BulkAll which is a saner default

* fix audit reporting negative durations

* Add FailedOverOnAllNodes audit event

* BulkAll now handles bad responses from the _bulk itself as well and optionally bails out early

* Fixed tests now excepting FailedOverAllNodes

* ContinueAfterDroppedDocuments should not be tested for nullable arg in the code standards test

(cherry picked from commit ec5ef6f)

Author: Mpdreamz

src/Elasticsearch.Net/Auditing/Audit.cs

@@ -41,6 +41,7 @@ public Audit(AuditEvent type, DateTime started)
 		public override string ToString()
 		{
 			var took = Ended - Started;
+			if (took < TimeSpan.Zero) took = TimeSpan.Zero;
 			return $"Node: {Node?.Uri}, Event: {Event.GetStringValue()} NodeAlive: {Node?.IsAlive}, Took: {took}";
 		}
 	}

src/Elasticsearch.Net/Auditing/AuditEvent.cs

@@ -21,5 +21,6 @@ public enum AuditEvent
 		BadRequest,
 		NoNodesAttempted,
 		CancellationRequested,
+		FailedOverAllNodes,
 	}
 }