Support exporting and importing settings

[TheLastProject]

Low priority. Maybe a checkbox in the import/export screen? Many people use import/export to share cards with friends/family so we definitely shouldn't force it to import/export settings.

Asked by @Danny3 in #3222 (comment)

[Danny3]

Thanks for creating this!
I am OK with a checkbox in the import / export screen to make it optional.
For myself and probably for my family too, I would want to export and then import the settings too, but good to have it optional.
One small suggestion, that I think would be nice, at lest for me:
If I choose to also export the settings, I would want the file to have a suffix like:
-with-settings
-with_settings
While the import feature could most likely look inside the file and detect if the settings were exported too, I think it would be nice and easy to understand if the settings were exported too just by looking at the filename.

Another thing, if the app is not already doing this, I think the app version should also be exported into that file as in the future, when do app has some kind of major upgrades or breaking updates and someone is trying to import a file that is too old, some decisions could be made.