chore(shadertools): Improve ShaderModule typings

[ibgreen]

For #
Another stacked PR for ShaderInputs

Background

• The ShaderInputs PR required a pass on shader module typings,
• The sheer amount of code changes makes it desirable to land this first.
• In particular types now distinguish clearly between a module's Props vs Uniforms types
• (based on feedback that shadermodules should expose an abstract set of "props" that can be remapped against different uniforms without breaking apps, and if so particular attention should be given to the types of those abstract props as they are the surface towards the app).

Change List

• Shader modules

• Some cleanup of previous stacked PRs.

• I am not happy with the 1% coverage drop in this PR, but I can't quite spot what is driving it.