WIP: User imports

[BrainBacon]

Work in progress, but functional.

make a library module, make functions, static consts, and helper types public then use the module inside of your wgsl module.

Limitations:

• will only accept use statements in the glob format, e.g.

use foo::bar::*;

• will not work with qualified functions and types, e.g.

foo::bar::helper_function()

In Progress:

• Tests
• Documentation
• Error messages
• Example
• Formatting
• Checking if libraries imported from other crates works
• leading colon support ::
• commit clean up

[Sheldonfrith]

Have reviewed commit 7deaf49, all good. Will proceed to next commit.

[Sheldonfrith]

Looking at all the source code changes everything looks good. I think if we could add a quick example to the examples which uses this new import functionality in order to confirm it runs as expected that would be best, probably just copy existing example code but move some of the shader code to a different module that we then import.

[Sheldonfrith]

As mentioned above it would be ideal to have a new example in the examples directory which utilizes this new functionality. Feel free to copy an existing example, since the theoretically correct outputs for those have already been determined. And then just run bash pre-commit-tasks in the root directory and fix any clippy or fmt errors that come up and I'll merge it. Great work!