[WIP] 🌈 Colorful & Customizable ⚙️ Playground

[ochafik]

This is already deployed in https://ochafik.com/openscad2/ but there's a fair bit of work left before merging.

New features

• Color support in preview & render, including green faces for result of subtractions (fixes Color #7)
• Export to glTF (.glb), OFF, 3MF, X3D
• Customizer
• Switched viewer to https://modelviewer.dev/, which makes it AR-enabled on supported devices (e.g. iPhones) and incidentally preserves camera between edits (fixes Keep camera position between renders #22)
• Multimaterial export (BambuStudio/PrusaSlicer) with mapping of colors to closest filament color

TODOs

• Merge build: move WASM build options into CMakeLists.txt, remove unneeded steps openscad#5199
• Extract customizer as separate PR: add customizer #38
• Extract sounds as separate PR: Global F5/F6 bindings + familiar sound on F6 #39
• Remove JSZip dep (maybe send separate PR)
• Merge Color support in 3D rendering (includes OFF color import / export, green subtracted faces) openscad#5185
• Merge Color support for 3D rendering + export to glTF, Collada, STEP, PLY, X3D openscad#5180

Bonus points:

• Finish file support support adding files by URL (mount remote zips) / dropping files / resetting to default / underlying file content
• Drop suboptimal environment map in favour of actual lights (see Support KHR_lights_punctual extension google/model-viewer#4832)