Obtaining an authorization token is done in the RequestAdapter and not in middleware

[darrelmiller]

In order to decouple authorization from the native HTTP client library, the IAuthenticationProvider interface depends on the RequestInformation abstraction. The RequestInformation object is available in the RequestAdapter but does not get passed through to the middleware pipeline. In order to use the AuthenticationProvider during the middleware pipeline, the native request message would need to be translated back into a RequestInformation object which would be redundant.