Add opt-in plaintext DB: default it for mobile #6
Description
Some users are not a fan of the pin system (despite sadly misunderstanding that; without it, their messages and account data is completely readable by their phone and anyone who has access to it), despite this, it would indeed improve UX a lot by removing this step, particularly on mobile where users want instant access to their chats without waiting.
This setting will be available on all OS'es, and encryption-by-default will remain true on Desktop OS'es, but mobile will be moved to instead rely on the system's built-in authentication and encryption (Mobile passcodes, patterns, biometrics, etc), while this reduces Vector's local security, it harms nothing network-side, the user will simply be trusting their device and OS to be encrypting Vector's DB on their behalf.
