Migrated to Svelte 4 and SvelteKit 2, refactored most writable() instances

[gnomefire]

• Migrated to svelte 4 and updated all packages.
• Migrated to sveltekit 2
• Refactored instances of Writable() (probably still more to do on this front, but it seems to be working)
• Updated to use the newest node version (20.11.0)
• Updated package manager to pnpm (this is just a personal preference for efficiency)

TODO:
update all outdated dependencies
MUCH MORE

[netlify]

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[Myrmod]

• Migrated to svelte 4 and updated all packages.
• Migrated to sveltekit 2
• Refactored instances of Writable() (probably still more to do on this front, but it seems to be working)
• Updated to use the newest node version (20.11.0)
• Updated package manager to pnpm (this is just a personal preference for efficiency)

TODO: update all outdated dependencies MUCH MORE

Thank you for the updates and suggestions!

I have some notes though:

• Currently we have to use Node 18, since Netlify only supports NodeJS up to that version.
• The exports of JS files, instead of TS is intended and should remain. Not everyone uses TypeScript in their projects, and enforcing it in the package would make it harder to integrate the library in their projects. EDIT: DOESN'T MATTER, TypeScript is fine
• The change from npm to pnpm is totally fine
• do you really need @types/babylonjs?
• what is this package.json.bkp for?

I haven't been able to look into the project and svelte in a while, so I'm sorry for the missing updates. I'll try to assist you in updating as best I can.

Best regards and thank you