Replace unattended floppy disk archive with vvfat directory, remove mtools dependency
The unattended installer creates floppy images thanks to mtools/mcopy.
Instead, it should be able to use qemu vvfat support, which can be defined via libvirt, ex:
<disk type='dir' device='floppy'>
<driver name='qemu' type='fat'/>
<source dir='/var/somefiles'/>
<target dev='fda' bus='fdc'/>
<readonly/>
<address type='drive' controller='0' bus='0' target='0' unit='0'/>
</disk>