Ray Tracing Pipeline: Additional Docs and Bug Fixes

[ComfyFluffy]

Changes to examples

• Use perspective_rh instead of perspective_rh_gl for camera in ray tracing examples.
• Rename miss shader extension to rmiss, as this is the standard extension name for miss shader.
• Refactor TLAS builder function in examples to take multiple instances.

Bugs fixed

• Incorrectly copying handles when shader groups do not follow a specific arrangement.

Docs

• Docs for trace_rays.