Auth and users services

[iharsuvorau]

• [x] Security policy draft
• [x] Auth service interface
• [x] Auth service basic implementation
• [x] Users service interface
  • [x] Account management
  • [x] Secure password storage (twofish algorithm)
  • [x] Ability to add password recovery in the future
  • [x] Ability to introduce 2FA in the future
• [x] Users service implementation