feat: allow passing in the source file as a parameter about hevm HOT 2 OPEN

A simpler (and probably nicer) version would be to call solc on the given contract filename and parse the resulting output json directly. We could add a cli arg to allow users to choose a solc version, and perhaps respect any discovered remappings.txt files?

from hevm.

hm, yeah this could be a nice ux, I guess theres a few feature requests here:

1. making hevm exec aware of some project structure
2. being able to refer to artifacts from a solc output file by name
3. automatically calling the project build tool before running a contract

I think it would change the character of the exec subcommand a little, which up until now has been more of a one shot tool for ad hoc analysis, and the unit testing interface under dapp-test has been used for more structured work in an existing project, but it seems doable without breaking existing workflows. I would be open to merging if someone wants to do the work and make a PR.

from hevm.