Basic cloud-init guide.

[Tinyblargon]

Create/update a basic cloud-init guide to help users get started. Users are now relying on out of date guides to create templates, and this leads to lots of issues where it isn't clear if there was something wrong with the Terraform provider or if it was user error.

• Should include all steps like creating base vm and importing disk image.
• Supply a minimal terraform configuration to be able to create a new vm from the template.
• Use the latest stable Debian and Ubuntu for the guide.

#1104