Fix Gateway VM bootstrap process

The VM bootstrapping process relies on the VM being bootstrapped having a DHCP server on it's various NICs that will give it an IP and tell it how to access the internet. Our gateway VMs do not have access to such a thing during their boot process, as they are expected to be the DHCP server. Technically they should be able to use oldlan to get internet access, but that doesn't seem to be working in practice. This improves the robustness of the cloud-init configuration options, and uses the new options to make cloud-init setup static IP addressing.