builder/virtualbox: set Tpl on VBoxManage
builder/virtualbox/ovf: StepImport to import an OVF
builder/virtualbox/ovf: re-order some steps
builder/virtualbox/ovf: specify name for import
website: document the virtualbox-ovf builder
plugin/builder-virtualbox-ovf
Rename "virtualbox" builder to "virtualbox-iso"
command/fix: add fixer to fix virtualbox to virtualbox-iso