Criterion benchmarks for Plutus scripts

[srid]

Can we inject ExBudget and size into criterion?

cf. https://github.com/input-output-hk/plutus/blob/1f31e640e8a258185db01fa899da63f9018c0e85/plutus-core/cost-model/budgeting-bench/Common.hs#L163-L183

Use this in the Gift contract; but it wouldn't be accurate until #27 ... however, we could benchmark on #28.

• Benchmarks for contract validator scripts (no criterion) (Benchmark contract validators #30)
• Benchmarks for arbitrary scripts (and review using criterion here for all benchmarks)