docs: Add layers settings schema

[christophe-lunarg]

Too frequently, we are getting SDK issues regarding the validation layer manifest not being correct.

This is because it's not validated in the repository. For this, it needs to get access to the layers settings schema.

With the conflexity of the ecosystem continuing to increase, we are going to rely more and more on layer settings so we must have test running when PR are made.

Adding the schema here will enable any layer repository to access the file and add a CMake custom target to check the build manifest is correct.

[spencer-lunarg]

I guess my question is what happens when the schema changes, we going to update it here? Would it be better for layer repos to just add CI to download the JSON and check against it instead?

[christophe-lunarg]

I guess my question is what happens when the schema changes, we going to update it here? Would it be better for layer repos to just add CI to download the JSON and check against it instead?

@spencer-lunarg this is not clear to me.

Isn't downloading is what's it's done with this repository? Why creating yet another mecanisum?

The schema is backward compatible. If a new capability is implemented, the schema is updated and a layer can't use that new capability until the schema is updated.

[spencer-lunarg]

ok, so it is here, we still need some CI job to verify the VVL json settings right? Like what does the VVL logic look like? It will need the .json file regardless, my question what is the reason to have it in VUL vs just having it download it from the Schema repo?

[spencer-lunarg]

sorry, I see what you mean now making it a cmake step... ok, fair, honestly it is probably fine

[christophe-lunarg]

ok, so it is here, we still need some CI job to verify the VVL json settings right? Like what does the VVL logic look like? It will need the .json file regardless, my question what is the reason to have it in VUL vs just having it download it from the Schema repo?

What do you mean by "just" download it, how that work?

This file is not in the schema repo.

[spencer-lunarg]

This file is not in the schema repo.

again, never understand this schema stuff, it feels like magic where these schema appear from, but this is fine, will get the VVL change up now