Include native comments in export/import JSON

When exporting ghost content from the Labs section of the settings page, native comments are not included in the created JSON (using ghost 5.3.0 running in Docker with MySQL 8 as backend).

This makes it difficult to migrate from self-hosted ghost (with native comments enabled) to ghost Pro.
And the other way around too, of course.

Suggestion:
Include comments in the export/import JSON file.