Command-line utility to run evals

[miltondp]

In the future, instead of that ugly, super-long relative path I'm using, we could have a command line script installed in the environment since we are doing an editable local installation of this package.
It would be something like: manubot-evals run (not sure about the manubot-evals name), manubot-evals view etc.

Originally posted by @miltondp in #1 (comment)