[FR] export and import single appflowy format pages, settings

### Description

I'm not sure what the latest status is on backup and export/import.
1) I would be happy if individual pages with their subpages could be exported in an "AppFlowy format" that also contains the full formatting. Just as it is currently possible with the External AppFlowy Folder, but only page by page. If you export a page as a backup and import it again later, it should look exactly the same as when it was exported. Is this planned or does it involve a lot of effort?
2) Then it would also be very practical if some of the settings (appearance, language, user: name, notifications and shortcuts) could also be exported and imported. If you start with a "new" AppFlowy, you would not always have to make all the settings manually again. This would be a great advantage, especially for the many shortcuts! Is that planned? By the way, I would like to see this function for all software.

### Impact

easy data migration

### Additional Context

_No response_