Assessment tool: comment field is added to every question

In the assessment tool for tests comments can be added to manual correction question types (drawing, file upload, essay). comment is also need for all other question types.

Comment can be added by "Assessor" and is saved per question. In the result report for the participant, the comments should be visible, connected to the questions (not like now 1 comment field for all questions together).
in the correction mode, the correct solution as well as the answer of the participant need to be shown, so the "assessor" is able to compare.

to be able to use the comment field in the assessment tool a manual correction is mandatory.
(same issue as OO-2658, which has been deleted therefore)

Intern: CL-691