Consider terragrunt catalog/scaffold support

[JohannesRudolph]

This is more of a long term design consideration. collie started implementing collie kit import and collie kit apply logic long before terragrunt added support for the new terragrunt catalog and terragrunt scaffold commands, which provide similar functionality.

As our aim with collie is to provide a small UX/DX focused CLI instead of implementing a bunch of "proprietary" custom logic, we may consider adopting these features from terragrunt instead of rolling our own. However, since the current implementation of both of kit import and kit apply is not overly complex, there's no strong reason to pursue this right now.

Hence opening this issue for collecting ideas for further consideration.