Support duplicate contract names

Right now contract names are expected to be unique by the `fuzzing` package (but is supported by `compilation`). Instead we should come up with some contract ID or something similar to differentiate contracts. It has to factor in source file path. It needs to be human readable and intuitive (or we need an alternate approach), as the config file will have users specifying contract names for deployment order (per #11)

This is very low priority for now and not being considered yet.

Start by reading how the fuzzing and compilation packages currently identify contract names, then review the configuration needs described for deployment order in #11. Define an approach that distinguishes contracts using their source file paths while remaining human-readable and intuitive for configuration users.

Written by the indexing model from the issue text.