User boolean fields

Check all boolean fields in User entity and make them non-nullable (only true and false allowed, but take care of default values)

AC

• Following fields in User entity are not nullable, with specified default value:
  • newsletter (false)
  • photosUseRight (false)
  • displayFullName (false)
  • markedForDelete (false)
  • isActive (true)
• Migrations are created to update existing NULL values to specified default value
• Tests are running