This makes it easier to spot syntax errors when editing the
class reference. The schema is referenced locally so validation
can still work offline.
Each class XML's schema conformance is also checked on GitHub Actions.
Convert GLTF Document to use ImporterMeshInstance3D.
Add a GLTFDocument extension list and an extension for converting the importer mesh instance 3d to mesh instance 3d.
Use GLTF module when the editor tools are disabled.
Modified the render server to be less restrictive on matching blend arrays and have more logging.
Misc bugs with multimesh.
Always index the meshes.
