Add logging to the TrackRequest middleware

[mattrayner]

The Problem

When debugging a Ruby application by reviewing logs after the fact, it would be useful to know the ApplicationInsights Request-Id for further investigation.

Proposed Solution

It would be good to add logging both before a request is executed, and after a request is completed - noting the Request-Id value as mentioned in the examples here:

https://github.com/dotnet/corefx/blob/master/src/System.Diagnostics.DiagnosticSource/src/HierarchicalRequestId.md#example

This would allow a user to know from application logs, what the ApplicationInsights ID is for a potentially problematic request