Adapting farmer benchmarks for existing plots and integrating them into CLI

I think we can go without criterion for this. As described in More rewards on smaller plots - #5 by nazar-pc it would probably be better to have a separate root command bench or benchmark on subspace-farmer, then we can have multiple subcommands starting with audit and have any CLI arguments we want there.

Criterion can be added later if necessary though. The initial goal would be to make command read farm information and being able to audit it in isolation without plotting or proving.

Somewhat complementary, when we add metrics to subspace-farmer we’ll be able to expose things like audit time per farm in there for easier analysis and visualization.