Use f1600 from keccak crate

[newpavlov]

I've implemented a stand-alone crate keccak which currently contains only f1600 function. (in future I plan to expand it with other keccak-f variants and keccak-p) The crate is licensed under CC0 terms and it's based on @Vurich's contribution. The main changes are use of custom unrolling macros (i.e. no dependency on crunchy) and disabled unrolling of rounds loop. The latter results in a better performance (~15-20% on my machine) and in a significantly smaller function size (~24 times), which proportionally improves compilation times, especially after recent regression in the compiler.

[eira-fransham]

I don't think there's any point depending on this within tiny-keccak. If your implementation is better then the consumers of tiny-keccak should just depend on your crate instead. The only improvement to the algorithm in this PR is rerolling the outer loop, and I think a better PR would be one that did that and that alone.

[newpavlov]

In future we plan to add wrappers around assembly from KeccakCodePackage which will be exposed in keccak through feature gate, so I don't think it will be a good idea to duplicate implementations. Either way it's your call, so you can close this PR if you want.