WebGPURenderer: Introduce hash-based cache key

[sunag]

Related issue: #29386, #29212 (comment)

Description

A numeric cache key brings a performance gain in the rendering cycle ( #29386 ) in addition to saving memory because it is just an integer instead of sometimes big strings.

As RenderObjects hashes inherited the individuality of RenderContext, the possibility of collision decreases, among other detail that can be improved in case of we encounter any collision issues.

I was thinking about using the getHash terminology but I had some conflicts with some existing functions.

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	687.32 170.19	687.32 170.19	+0 B +0 B
WebGPU	836.4 224.22	836.83 224.44	+422 B +224 B
WebGPU Nodes	835.91 224.09	836.34 224.32	+422 B +224 B

🌳 Bundle size after tree-shaking

Minimal build including a renderer, camera, empty scene, and dependencies.

	Before	After	Diff
WebGL	463.24 111.86	463.24 111.86	+0 B +0 B
WebGPU	532.82 143.71	533.19 143.85	+377 B +142 B
WebGPU Nodes	489.16 133.47	489.54 133.61	+377 B +139 B