hypervisor: Red Hat tunning

This patch aims to configure compute nodes belong Red Hat requirements:
- load KVM module
- Ensure "tuned" service is running
- Activate "virtual-host" profile  in "tuned" service
- Ignore libvirt-guests on boot

This requirements are inspired by Packstack deployment tool which is
designed to run on RHEL / Fedora systems.

Signed-off-by: Emilien Macchi <emilien.macchi@enovance.com>