Automatically find the StoragePool in case the Boxes one is not found (and move images accordingly)
If a user moves their /home folder around or uses symlinks/bind-mount for it, libvirt won't be able to find the "gnome-boxes" storage pool. It should be enough to use g_get_user_config/data/cache_dir functions to discover the new location, but the images (present in datadir/
package-name/images) need to be moved to the new prefix.
*Depending on the number of VMs this operation can take hours (moving disks around).