rewrite: Module output and base architecture

[Friz64]

This is based on #745 and eddyb's C parsing PR (Friz64#1). This PR will be rebased once these are merged.

I only implemented the most basic of struct outputs to have something to work with, extending that is the next step.

[stefnotch]

This looks very promising.
On that note, I would be happy to assist if there's anything you need, from small testing tasks to implementing some tricky features.

[Friz64]

Sure, the next step in my mind would be to actually implement struct/union generation. For that we need lifetime propagation.

I think it would be convenient to be able to discuss this in some kind of group chat for ash development. I'd usually use Discord for this, but I'm open to suggestions as I'm not adamant on it.

[MarijnS95]

@Friz64 there is a gitter instance for this repository. Link should be in the readme, it's using the old repo url because gitter couldn't migrate.

You can use various clients like Matrix to connect.

[Friz64]

I've gone ahead and touched up this PR from the ground up.

The module structure is now extensions at the top level just like current ash, Vulkan feature levels at vk1_0, vk1_1 etc just like erupt, and Vulkan Video at video. Not that it reaaally matters, cause the vk re-export is also still there ofc.