[feat]: cloud backups

[dr-bonez]

Prerequisites

• I have searched for existing issues that already suggest this feature, without success.

Describe the Feature Request

allow backing up to cloud data storage providers such as dropbox, google drive, ftp servers, etc.

Describe the Use Case

This will allow more reliable automated backups, and protect users from data loss in the event of i.e. a house burning down, which would presumably destroy lan backups in addition to the device itself.

Describe Preferred Solution

Add a backup target for WebDAV, FTP, and any other protocol we can that is used by popular cloud providers. This requires using a FUSE module for each.

Describe Alternatives

No response

Anything else?

No response

[MattDHill]

Dropbox, Drive, iCloud, OneDrive

[kn0wmad]

If API is similar enough, can we include Mega?

A bit cheaper, include e2ee (maybe not relevant, since backups are encrypted already), ostensibly Freedom-principled