Move all configuration to more generic recipes, so that recipes can be shared
between software releases.

Disable previous recipers.

Slave configuration is not finished and need to be migrated.
It is needed to publish the slave URL.

Hardcoded vifib rewrite map has been removed.
It is needed to use a frontend slave instance to achieve this functionnality.
This means, frontend slave instances need more parameters.

NBD software release has been merged into the KVM software release as a
software type. It allows to use the same binary for nbd and kvm, and so, save
space on servers and ease maintainance.

Remove software release's python dependency.

Add more promises to check status of nbd, kvm and frontend.

slapmonitor functionnality has to be restored.