App Backups

[nplasterer]

To make a really good app experience we need to allow application back ups.

Using the existing message history work lets expose a few more functions

• Ability to export all message history in some sort of format that can be stored in a external DB (iCloud, Google Drive etc..)
  • Ability to specify a time range for message history based off of last backup
• Ability to import this message history back into the libxmtp database

[nplasterer]

Per discussions this is not trivial. On login to a new device even if into the same app you will be using a new installation. This means you still need something to add you to all your existing conversations and groups for the import of messages to be useful.
A possible initial stop gap would be to add this functionality only for preference records like consent at first.

[nplasterer]

Backup the entire libxmtpDB. Installation keys stored in icloud. Revoke the installation key if it gets compromised.