Support interactive network console when PXE booting

As a user of the Agent-based Installer(ABI), I want to be able to perform the customizations via agent-tui in case of PXE booting so that I can modify network settings.

Implementation details:

Create a new baseImage asset that gets inherited by agentImage and agentpxefiles. The baseImage prepares the initrd along with the necessary ignition and the network tui which is now read by agentImage and agentpxefiles.