Consolidate some models into a single model using submodels

[SaintWish]

It would be really helpful to consolidate similar models into a single file by just making them submodels. This would decrease the amount of models we would have to precache.

[tschumann]

Are the model sources available for most models?

[SaintWish]

No, we're missing a majority of model sources if not all of them.

Most of the models are already consolidated together, but I think there's some that could still.