Binary database storage with user data encryption

[lightyears1998]

• Upgrade outdated backend software.
• Allow quick register a user from an open-registering backend.
• Add logic to remove non-active user from user.
• Derive private key from user password (the original one, not the sha256 hash, because server should know about the hash to recognize the user). When sync, encrypt container and decrypt from local device only.

This must be done the before the v2 public release to ensure user privacy.