Docs: Add plugins and libraries page

[gkjohnson]

Fix #19353

Description

Here's a first pass at a page documenting some external libraries and plugins that work with three.js or are otherwise solutions to common questions in three.js (physics engines, etc). Here's the live link:

https://raw.githack.com/gkjohnson/three.js/plugins-and-libraries/docs/#manual/en/introduction/Libraries-and-Plugins

I tried to add packages that seemed reasonably maintained but it might be worth documenting out of date ones in case someone wants to submit PRs / update them. I haven't added them in this PR but here are some other out of date packages that I still see come up every once and awhile:

• partykals
• ShaderParticleEngine
• TrailRendererJS
• Wagner Postprocessing
• THREE.MeshLine
• dat.guiVR (which does have a maintained fork for WebXR here)
• three_js_outline
• THREE.DrawCallInspector
• THREE.BLAS
• GSAP
• tween.js

The list here is what I had at the forefront of my mind -- others should feel free to add / suggest more!

[donmccurdy]

Under "Wrappers and Frameworks", it might be nice to include ECSY.

For categories where three.js itself offers an alternative, we should probably call that out so users don't jump directly to the external option or assume that's the default choice. For example:

---

File Formats

In addition to the official three.js loaders, support for some additional formats is available through external libraries.

• urdf-loader
• ...

[gkjohnson]

@donmccurdy Done! Added both.

[mrdoob]

@gkjohnson Do you mind adding OBJLoader2 to the list too? See #21014

[gkjohnson]

@gkjohnson Do you mind adding OBJLoader2 to the list too? See #21014

Added!

[mrdoob]

Thanks!