draft to illustrate adding routing context to grpc

[doctorpangloss]

Motivation:

This is a much simpler way to add auth and other features. I blew away a lot of Jotschi's changes. Once a RoutingContext is exposed to server stubs / whatever you want to process your grpc stuff with, you can use the pre-existing vertx-web-auth ecosystem flawlessly.

Additionally, this code allows you to return a StatusException and correctly send the status to the client.

Conformance:

You should have signed the Eclipse Contributor Agreement as explained in https://github.com/eclipse/vert.x/blob/master/CONTRIBUTING.md
Please also make sure you adhere to the code style guidelines: https://github.com/vert-x3/wiki/wiki/Vert.x-code-style-guidelines

[vietj]

this project cannot depend on vertx-web