Switch sr-arithmetic benchmarking to criterion (#3902)

* Change DefaultMaxDepth from 1024 to 32

* Switch sr-arithmetic benchmarking to criterion

* Update core/sr-arithmetic/Cargo.toml

Co-Authored-By: Bastian Köcher <bkchr@users.noreply.github.com>

* Update core/sr-arithmetic/benches/bench.rs

Co-Authored-By: Bastian Köcher <bkchr@users.noreply.github.com>

* Test on variable limb lengths

* Change license

* Rework division