import/lightning: Allow creation of parent directories for sorted-kv-dir

## Enhancement

Currently, when using Lightning's import functionality, an error is returned if the parent directory of the `sorted-kv-dir` specified in the configuration does not exist. We could enhance this behavior by automatically creating the parent directory along with `sorted-kv-dir`. This change would provide greater flexibility for users, allowing them to specify paths without worrying about manually creating the parent directories first.