Draft: radv: Some meson fixes, small refactors and a radv_pipeline.c cleanup proposal

Patches that should go in:

• f424cb1e radv: Add radv_ray_tracing.h to meson.build
• 521edcb9 radv: Add radv_constants.h to meson.build
• a7b2f872 radv: Make nir_sort_hit_pair static
• 0c20c367 radv: Prefix common ray tracing helpers with radv_

Proposals (Something along the lines of !17811 (merged)):

• 172643a2 radv: Rename radv_pipeline_rt (make naming consistent width 97655bb7 and 06b89ac2)
• 26e8f260 radv: Rename radv_rt_common to radv_ray_tracing (make naming consistent with 172643a2)
• 97655bb7 radv: Move compute pipelines out of radv_pipeline
• 06b89ac2 radv: Move graphics pipelines out of radv_pipeline