Revamp "AnimationContext" Docs, now called "AnimTaskQueue"

[fig02]

I got sent down a rabbit hole while doing Player docs which required a better understanding of what we used to call "AnimationContext".

After learning about it, I decided the current names for basically all of this system could be improved. After a few iterations I ended up calling it the "AnimTaskQueue" and changed a bunch of terminology throughout. It sounds quite generic, but it kinda has to be. The various tasks aren't very correlated, other than the fact that they are related to animations.

All of the relevant functions in skelanime have comments at the top that hopefully explain everything, but let me know if anything else needs to be clarified.