Import/export user data and settings

Importing user data and settings from anywhere else

Allow users to export data including app settings and profile customization (icon, display name, etc), to some format like JSON maybe. Then, also allow users to import app settings and profile customization from JSON. Then, people can create scripts or tools to get your settings and profile from Stoat, or Matrix, or legally questionable Discord, then import them to Fluxer, making switching easier