Add CLI arg to point the project folder to a specific path

[DeflateAwning]

The current workflow is fine for demos, but it's super non-standard for a program to generate more files in its own GitHub repo, which aren't .gitignore'd.

Especially with the new addition of the --config incremental mode, this is important so that ChatDev can be pointed to a codebase location elsewhere.

Update: looks like this is implemented via the --code-path arg, for incremental mode only. This issue is a request to extend this functionality to non-incremental mode as well.