Data Backup

[VolkerSchiewe]

Scope of the feature

After adding the feature to recover the user identity based on the seed phrase, the user should also be able to recover his/her user data.

The data backup should be encrypted so that only the user can access it.
To offer a high usability for the user the backup can be stored on a server and automatically updated.
For users that want more independence there should be an option to perform manual backups.