Improve benchmarking

[kirk-baird]

What is the issue

Benchmarking currently consists of one file BenchtestALL.rs. Thus should be updated to the cargo bench format.

Steps to resolve

• Move the file to a folder in the top level called benches
• Split the file into multiple files, one for each individual protocol.
• Modify Cargo.toml to include a [[bench]] for each of the above files. Consider adding a feature bench for running the benches.

Update

Benchmarking has been updated to use criterion. However, there are still plenty more functions worth benchmarking, existing benchmarks for curves such as ED25519 should also be updated.