[feature] cross platform backup/restore

[pexner]

IIt would be nice to have a kind of backup and restore function for settings (except account credentials) and instances.
Using a kind of backup function which compresses ALL (settings and instances) or export/import function for instances.
Like this, it'll be possible to move to a different OS or being able to send an instance to a friend.
Backup ALL: will create a backup-file of all settings and instances.
Restore ALL: will restore the backup-file and replace everything.
Export instance: will create a compressed instance-file (which can be sent to a different PC / OS)
Import instance: will import the instance.

Is this technically possible?

pe

[02JanDal]

Duplicate of #366. This one was opened earlier, but that one has a bit more discussion.