Reimplemented glTF Import/Export

[dinomut1]

Summary

The editor "Import Scene" and "Export Scene" buttons now handle glTF equivalents of scene.json files.
The GLTFExporter class has been replaced.
disposeScene now cleans up the ECS system.
Partially implemented JSON schemas for all scene components in glTF extension form. Also added schemas of glTF format for eventual use in validation.

Checklist

• Pre-push checks pass npm run check
  • Linter passing via npm run lint
  • Unit & Integration tests passing via npm run test:packages
  • Docker build process passing via npm run build-client
• If this PR is still a WIP, convert to a draft
• When this PR is ready, mark it as "Ready for review"
• Changes have been manually QA'd
• Changes reviewed by at least 2 approved reviewers

References

#5518

QA Steps

1. git checkout pr_branch_name
2. npm install
3. npm run dev-reinit
4. npm run dev

List any additional steps required to QA the changes of this PR, as well as any supplemental images or videos.

Reviewers

Reviewers for this PR