[Generic] Allow import of skeleton based animations

[Ithamar]

The "Generic" plugin currently only supports import/export of OBJ files, but it would be fairly simply to allow import/export of DAE/GLTF/GLB files, and import of FBX files, including skeleton/animation data.

With a bit of work CMM could basically "render" the keyframes to get a simple list of remapped vertices, basically enabling it to be exported to a format the classic Carnivores games can deal with.

This would be one-way, unless somebody can point me to a good source of information of how to do it in reverse ;)