Integrate benchmarks from rust-fil-proofs.

[porcuquine]

• Add constituent benchmark files manually.
• Add jq script to combine them and create git-hash-named input file.
• Add make target to do this.
• Add functions to read, parse, and structure benchmark json.
• Add helpers to extract needed zigzag data.
• Replace hard-coded hash times (in and out of circuit) and constraint numbers with bench info.
• In order to keep times comparable, introduce baseline-mhz and scale seal/replication times to this.