[Feature] Carl integration {WIP}

Ok, so this one is a bit tedious and will take a bit. Here is what needs to be done to bring a model in and make it work right with existing animations and a HMD:

 - [x] First thing you need to do is remove skin modifier on the character. We need to modify the mesh
 - [x] Second thing is we need to do is remove the head and fill the whole we will make because of it. If we leave the head the user will get artefacts from being inside the mesh even though the materials are one sided.
 - [x] Then we need to remove the skeleton. This is just deleting it since we already removed the dependency in the skin modifier when we deleted it
 - [x] Then we need to bring in the skeleton that has the animations in the engine we want to reuse. To do this we find the skeletal asset in the engine and export it and then bring it into the scene in our 3D modelling program.
 - [x] Then we add a skin modifier, add all the bones back in, and repaint the weights.


In theory we could try to retarget the animations to the new skeleton but that currently only seems to work well when they are the same skeleton (or very very similar) at a different scale. Unfortunately that doesn't work on this one because this guys is rigged for things like facial  animations.