feat: allow scikit-package-workspace to automatically create the project-level cookiecutter.json

[ycexiao]

What problem does this PR address?

Closes #16

What should the reviewer(s) do?

Please check the modifications.

• This PR introduces a public-facing change (e.g., figures, CLI input/output, API).
  • Documentation (e.g., tutorials, examples, README) has been updated.
  • A tracking issue or plan to update documentation exists.
• This PR affects internal functionality only (no user-facing change).

[ycexiao]

@sbillinge @bobleesj , it's ready for review.

[sbillinge]

as in the other PR, pleaes paste screenshots of it working. Thanks.

[ycexiao]

@sbillinge
Run package create workspace in a path without cookiecutter.json:

cookiecutter is created in the generated directory foo.

.
├── foo
│   ├── cookiecutter.json
│   ├── ...
└── ...

Run package create workspace inside foo directory:

[bobleesj]

@ycexiao Looks good to me!