Create app data migration flow between NC Apple Account app and OHF Apple Account app

### Description

To cause less impact as possible during app migration from Nabu Casa Apple Account to Open Home Foundation Apple Account, we need to create a migration flow where data will be transferred directly from the "old" app to the new one, with intuitive UI and clear communicated information regarding what will be migrate and what wont be migrated.

### Additional context

_No response_

The issue does not name any files, tests, or entry points. Start by mapping the existing data stored by the Nabu Casa Apple Account app and the Open Home Foundation Apple Account app, then define which data must transfer and the UI information needed to make the migration complete and understandable.

Written by the indexing model from the issue text.