Add option to enable N1QL timing logging

"Currently when a query is executed by the .NET client, it flows through a couple of layers before being dispatched by an HTTP library. The results are then come back with a set of metrics (optional, but on by default). While it is possible to understand what is happening with standard logging, sampling and logging response times of query requests requires code changes on the part of a developer.

The goal of the project is to add a simple configuration option to log three things. First, the elapsed time observed by the client library. Second, the elapsed time measured at the cluster. Finally, the statement being sent by the client in the HTTP request."