Split up "points" and "grade"

[TethysSvensson]

I would like to split up "points" and "grade" in the grade.yaml file. I have way too many times changed the wrong number. So far it has not resulted in any bad feedback, but is it only a matter of time before I mess up without noticing.

[kfl]

Would it help to rename grade to points and points to possible-points?

[TethysSvensson]

Probably a bit. Not having the strings be the same length would make it easier.

Though I do not understand why the field is even needed since it is also present in the template.