core: use AddVmParameters for other add-vm commands

Final step in making AddVmParameters the parameters class for all basic
add-vm commands: AddVmParameters is now used as a parameters class for
AddVmFromTemplate and AddVm commands.

Change-Id: I64943e1538c6c796ab0cdf4da71ca820ff63b0ee
Signed-off-by: Arik Hadas <ahadas@redhat.com>