LDEV-3644 Store answer grade (%) sum in question so front-end knows whether the question was answered correctly/partially/incorrectly even if mark is 0.
LDEV-3315: Prevent XSS attach when recovering password. Do not give away information that an email is assigned to multiple users. Do not give away DB structure when an error occurs.
LDEV-3315: Prevent XSS attach when recovering password. Do not give away information that an email is assigned to multiple users. Do not give away DB structure when an error occurs.