[naga] Move and rename back/spv/ray.rs -> back/spv/ray/query.rs

[Vecvec]

Connections
Precursor to spv backend of #6760

Description
spv-out's ray.rs is large (just over 2000 lines of code). Since ray tracing pipelines are intended to be added alongside ray queries, moving ray query writing to a sub module (and when added, ray tracing pipeline writing in a different sub-module) is a way prevent the module growing much larger (query.rs probably still needs to be split, but there isn't a good divide).

Testing
Just a refactor

Squash or Rebase?
Squash

Checklist

• Run cargo fmt.
• Run cargo clippy --tests.
• Run cargo xtask test to run tests.
• [-] If this contains user-facing changes, add a CHANGELOG.md entry. Internal changes only.