RawTexture: Rename to ExternalTexture.

[Mugen87]

Related issue: #31487

Description

As suggested in #31487 (comment).

[github-actions]

📦 Bundle size

Full ESM build, minified and gzipped.

	Before	After	Diff
WebGL	338.82 79.08	338.84 79.07	+15 B -1 B
WebGPU	566.16 156.5	566.16 156.5	+0 B +0 B
WebGPU Nodes	564.77 156.26	564.77 156.26	+0 B +0 B

🌳 Bundle size after tree-shaking

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

	Before	After	Diff
WebGL	470.25 113.78	470.26 113.78	+15 B -1 B
WebGPU	637.38 172.47	637.38 172.47	+0 B +0 B
WebGPU Nodes	592.02 161.71	592.02 161.71	+0 B +0 B

[sunag]

Interesting, I was thinking of using ExternalTexture name to potentially bridge a gap with texture_external from WebGPUBackend.

[mrdoob]

https://webgpufundamentals.org/webgpu/lessons/webgpu-textures-external-video.html 👀

Maybe like we can reuse it?

[sunag]

Yes, but it is still limited for our applications in general, it would not be for now anyway.