Remove the ComponentBytes and AsPixels traits

[ripytide]

I don't see the utility of the ComponentBytes and AsPixels traits compared to a user simply using bytemuck's cast_slice() and cast_slice_mut() methods. This could easily be achieved by optionally implementing bytemuck::Pod for all the pixel structs. Then a user could enable that crate-feature and use bytemuck to do conversions as they need.

In addition, having an crate-local implementation has had soundness flaws in the past in #35 so removing it would reduce that risk.

[ripytide]

Also mentioned in #39 (comment)

[kornelski]

The only issue is that bytemuck's syntax is more verbose, since cast_slice() etc are not trait methods, but standalone functions in the bytemuck crate.