Assessment: implement more score options for gap text

Assessment, question type "gap text":

In certain cases an answer in a gap text can be partly valid. This is not identical with an alternative word (synonym) which would also give a full score. Instead, an answer can be almost correct and would thus be rated with e.g. 0.5 points.

Example:

• "magnesium chloride" -> full score (1 point)
• "magnesium chlorine" -> answer is almost correct (0.5 points)

See spec (German only)

frentix internal

https://office.bexio.com/index.php/pr_project/showPackage/packageId/109