[FYRA-390] Thinking about the future of Katsu

[lleyton]

There are questions I've been thinking to myself about Katsu, namely:

• How does multi-distro support look? (do we want that?)
• What is an image builder? What outputs should we support?
• What is Katsu's place in a world with mkosi?

_FYRA-390

[korewaChino]

build everything as oci containers