feat(cli): add CLI support

[richrdkng]

🚀 Description

The feature to be able to call @nodewell/path using npx with basic CLI commands:

• init: create initial .pathsrc (decide what the default name should be, also provide an option to change)
• ls / list: list the default / available paths for the current project / package

💡 Solution

Implement a bin folder (and also add a bin entry in package.json) with a basic CLI.