feat: add board import and export

[luka-nextcloud]

• Resolves: #
• Target version: main

Summary

It makes it possible to export and import a deck board as a JSON/CSV file. CSV is only for export while JSON works for both import and export.

Video recording

demo.webm

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Documentation (manuals or wiki) has been updated or is not required

[elzody]

It works quite well, the only thing I noticed was that when I upload a clearly incorrect .json file to see what it does, it throws an error (as expected) but with the actual log message that you would see in the nextcloud.log file:

"OCA\\Deck\\Service\\Importer\\BoardImportService::setData(): Argument #1 ($data) must be of type stdClass, string given, called in /var/www/master/apps-extra/deck/lib/Service/Importer/BoardImportService.php on line 123"

Maybe instead it should display something more readable, and also something that doesn't expose the internal path of some of the files (e.g. the /var/www/...)

By the way, I am talking about the error message that gets displayed in the top right to the user.

[elzody]

Seems good to me now.