v0.13.0-rc.0

This commit presents the following changes: (#282)

- Removel of deprecated templates:
	Templates that are no longer in use should not be deployed on the
	client's cluster, so they were removed (if they are needed for old
	VMs, they exist on a cluster from a previous deployment.

- _linux.yaml Embedded into variant templates:
	In order to support fine-tuning of specific linux OSs without
	affecting others, the _linux.yaml template was embedded into
	all linux variants templates

- vm.kubevirt.io/validation annotation was introduced:
	In order to provide an easy upgrade for templates, the 'validation'
	label was moved to the processed VM from the parent template.
	This change breaks the dependency of the VM in the template
	during validation, and allows us the freedom to upgrade
	templates

Signed-off-by: Omer Yahud <[email protected]>