[pve-devel] Set VirIO as default devices for Linux VMs (with patches)

[Emmanuel Kasper]

(resending as the patch serie was missing from previous mail)

This patch series adds capabilities to store Qemu Wizard Defaults, and
use these capabilities
to set virtio by default for Linux machines.

Changes since V2:
 * listen to 'radiogroup' events in OSTypeEdit instead of setting a
 listener to each radio button
  * do not declare components alias with an array when the aliases
  containt a single value

  Implementation:
  We listen for the 'change' event sent by the radiogroup, and changes the
  value of the target controller.
  This works correctly because all panels belonging to the wizard
  are available in the DOM from the begining, and because the OS selection
  panel is before the hard disk and network card panels.
  The defaults are stored in a singleton class (automatically instanced by
  the framework) so that they do not end up in the global namespace.

  Please note that if for instance, you select the Linux OS, then select
  a alternate controller, then go back and switch to another OS, then
  your alternate controller selection is lost. This is intentional as
  it would leave the user wiht a suboptimal controller ( ie VirtIO still
  selected when you create a Other OS machine type )

  This is similar to oVirt/VirtualBox who preselect different kind of
  controllers  based on target guest OS.