spec: Move common files and dependencies to libvirt-daemon-common
Introduce a new subpackage libvirt-daemon-common and move virt-admin,
virt-host-validate, virt-ssh-helper, libvirt-guests and miscellaneous
files/directories to it. Also move common dependencies to the new
subpackage. These files, utilities, and dependecies are used by other
core libvirt daemons