Fix Blender Exporter rotation issues

[mrdoob]

As noted in #12987 (comment), by using the glTF exporter as reference we should be able to finally solve the rotation issues.

Relevant code:

https://github.com/KhronosGroup/glTF-Blender-Exporter/blob/v1.0.0/scripts/addons/io_scene_gltf2/gltf2_extract.py#L34-L60

https://github.com/KhronosGroup/glTF-Blender-Exporter/blob/v1.0.0/scripts/addons/io_scene_gltf2/gltf2_generate.py#L1356

https://github.com/KhronosGroup/glTF-Blender-Exporter/blob/v1.0.0/scripts/addons/io_scene_gltf2/gltf2_generate.py#L1487

Test scene:

#12987 (comment)

[Mugen87]

The JSON Blender exporter has been removed with R93 (#14117).

Also see: https://threejs.org/docs/#manual/introduction/Loading-3D-models