Secure Vagrant REST API Communications

[JoelProminic]

We would like to revisit the idea of setting up remote Vagrant Instances for customers. One of the concerns we have for this is making sure that the connection through the Vagrant REST Interface is secure.

We will need to make sure we use SSL/TLS for the requests. We currently use http as the base URL for the SHI instances. I think SSL is supported but I need to review why this was not available on the SHI instances. We will need to work with @MarkProminic for the server side changes on this.

We'll also probably want some sort of authentication for the requests, like a password or token. We could consider doing IP-based restrictions, but the IP could change frequenlty for some users.