Adding Autofac as an external container and to use it for DI in ASP.NET MVC endpoint.

WIP - Code changes complete -- needs review and more testing. 

- Relates to #303 
- Added autofac as a dependency for MVC endpoints
- Usign DI using Autofac directly and changed the web initialization to use the autofac container. 
- Removed the old files that were being used for DI namely, `ConfigureMvcDependencyInjection`, `NServiceBusDependencyResolverAdapter` and `NServiceBusControllerActivator`