Move `anim` example animation data out of source code.

[vitvakatu]

It was useful in the past, but now we have gltf loading and ability to modify geometry.

[kvark]

I think glTF loading is a bit of an overkill for demonstration of our basic animation skills. Having a separate dedicated example should still make sense.

[vitvakatu]

I suggest at least move the animation data out of the file. My IDE is a little bit unhappy while scrolling, and so am I. I'll think about it.

And yes, after some meditation the idea of removing example completely doesn't look shiny as it was.