Allow configuring the source directory

[TomAFrench]

Problem

I mentioned in #1009 (comment) that foundry projects tend to use the src directory for contracts. This opens up an issue for if you want to use Noir within a foundry project, by default these will write noir and solidity code to the same directory

Proposed solution

We could allow users to remap directories to custom paths by setting them in Nargo.toml similarly to how foundry does in foundry.toml.

https://book.getfoundry.sh/reference/config/project

Alternatives considered

There are alternatives for the meantime:

• Perform this remapping within foundry to move the solidity code rather than noir code.
• Move the Noir project into a different directory.

Additional context

No response

Submission Checklist

• Once I hit submit, I will assign this issue to the Project Board with the appropriate tags.