support scaffold step on installing modules

[danielroe]

this could be integrated with defineNuxtModule from nuxt/kit - modules could expose a step that allows scaffolding or running a small interactive CLI to set themselves up. For example, creating a config file, etc.

[pi0]

(self-assigned because it is already part of my todo. i guess we might need to think of an alternative meta exposed by modules btw for module initial scaffolding requirements)

[atinux]

We also need a way to know if the module was already installed and done without the CLI to make sure we can run those scripts / recipes.