Provide a built-in & secure backup & restore function

## Prerequisites
- [x] I have searched open and closed issues for duplicates.

## Feature
**Is your feature request related to a problem? Please describe.**
The problem is: data is quickly lost, due to hardware damage or accidental deletion by users. Also settings for the email client or the view mode of files in the file manager or settings in the Switchboard plugins may not be saved at all and have to be adjusted each time the system is migrated.

**Describe the solution you'd like**
I would like my operating system to support me by offering me the following options:
a) To have personal data backed up at regular intervals and to be able to access individual data/files or storage levels again on request or in case of need.
b) Periodically backup and restore system settings for all native app and system components.
c) Everything should be done encrypted if desired. Through a strong password/passphrase and also through two-factor authentication with Open Smart Cards such as the Nitrokey.
d) All this should happen in elementary style. Clever, integrated, easy to understand, graphically attractive and not overloaded with features. With the aim of also supporting non-technical users in protecting their data and saving their settings.

My suggestion would be system integration of BorgBackup https://github.com/borgbackup/borg#what-is-borgbackup

As an example: There is a visual integration in the form of an app called Vorta:
https://github.com/borgbase/vorta

**Existing work**
There certainly is, but I don't know a concrete example right now.