Add DependencyMonitor

[DeadlyEmbrace]

Description

Currently to monitor a dependency requires keeping track of a start date as well as a StopWatch to track time used. Create a class that will store these details and can be used with a simple using statement which will then flush data to ApplicationInsight

Tasks

• Create monitor class

[DeadlyEmbrace]

This requires a smarter way to handle the unit testing.
Take a look at this library, maybe there is a way to get the body in the correct format: https://github.com/Vycka/HttpMockSlim/blob/master/src/HttpMockSlim/HttpListener/HttpListenerServer.cs