Finish implementation of the named pipe transport

[davidfowl]

There's a prototype of the NamedPipeTransport in the experimental project. We'd like to move this over to the main project but it needs to be cleaned up and tested to make sure it works well.

• [ ] - Properly implement the NamedPipeConnectionContext. This needs to implement a bunch of features (like connection aborted)
• [ ] - Add extension method on both the server and client (ListenNamedPipe)
• [ ] - Add tests, lots and lots of tests