glTF exporter: performance: cache parent/children data to avoid bad .children performance when used a lot
Thanks rotoglup!

Fix when animation are not baked

    KHR_materials_ior
    KHR_materials_sheen
    KHR_materials_specular
    KHR_materials_transmission
    KHR_materials_variants
    KHR_materials_emissive_strength
    KHR_materials_volume

Documentation update is still in progress

Contributed by luzpaz.

Differential Revision: https://developer.blender.org/D15328

This can lead to wrong animation in some case.
Better to have good animation by default, even if bigger

When scene contains only 1 armature, it will export all actions, not only active + NLA