q5-webgpu: Major Refactoring

[quinton-ashley]

v3 is basically ready to release but I'd like to try doing some major refactoring first in the hopes of getting slightly better performance.

In JavaScript accessing properties on an object is just a bit slower than using local variables, but it does add up.

I'd sacrifice the organizational convenience of having q5-webgpu split into separate files if putting it in one file and using more local variables can improve performance. The total size of the one file would be ~65kb.

[quinton-ashley]

completed in v2.28.4