Authentication management

[Flofie]

Summary

This PR enables authentification on the API Gateway for remote services.

Linked Issue: #4

[claustres]

Thanks very much for your PR ! I will take some time to analyse this and merge.

By the way, would you be interested in writing an article in Medium for https://blog.feathersjs.com/ ? Or provide me with some inputs on your use case so I can write one by myself.

Thanks again

[claustres]

Your PR allowed me to work a bit on authentication and I actually updated your code before merging. I kept your improvement regarding hooks on remote services if you only want to expose an API gateway with auth. The example with docker works fine for this.

However I also extended tests to include a more general use case where you want to expose all nodes with auth and not only a gateway. In this specific case you protect your services on each node as usual with the authenticate Feathers hook, so that even when called from another node you have to use an authenticated client.