Benchmark of crypto functions as separate executable

[arhag]

#361 added a test case with does benchmarking for modular exponentiation. That should really be moved into a separate program for the purpose of benchmarking. Similarly, we should include benchmarking of other crypto functions:

• alt_bn128 math operations
• Signing and key recovery/validation for R1, K1, WebAuthn elliptic curves;
• hash functions exposed via host functions, e.g. SHA256, (benchmark both small and large sizes of messages to hash).