New method:
VBoxManage modifyvm "name of vm" --natpf1 "SSH,tcp,,2222,,22"
Old method:
VBoxManage setextradata "name of vm" "VBoxInternal/Devices/pcnet/0/LUN#0/Config/ssh/HostPort" 2222
VBoxManage setextradata "name of vm" "VBoxInternal/Devices/pcnet/0/LUN#0/Config/ssh/GuestPort" 22
VBoxManage setextradata "name of vm" "VBoxInternal/Devices/pcnet/0/LUN#0/Config/ssh/Protocol" TCP
