Remove cookie_factory

[Dinnerbone]

Note that the code is almost exactly 1:1 with what we were doing before, just manually - not through cookie_factory

That means the code is ugly and inefficient and spaghetti.

It was before, too, you just couldn't tell as easily :D

I intentionally am not cleaning the code up as part of this PR, to make the diff easier to check if any bugs crept in.

[CUB3D]

LGTM (well except the byteorder dep, but thats a discussion for another time)

[Dinnerbone]

Benchmark results, because I got curious:

cargo build (debug)

Code	Mean [s]	Min [s]	Max [s]	Relative
Master	35.360 ± 0.390	35.048	35.797	1.72 ± 0.02
This PR	20.587 ± 0.087	20.505	20.678	1.00

cargo build --release

Code	Mean [s]	Min [s]	Max [s]	Relative
Master	90.870 ± 0.407	90.456	91.270	3.80 ± 0.02
This PR	23.932 ± 0.010	23.921	23.941	1.00

[Dinnerbone]

LGTM (well except the byteorder dep, but thats a discussion for another time)

It's what we used in ruffle and I figured easy enough to switch; but it looks like we're exclusively BE, so switching away from this should be trivial in a followup if we wish