Resolve "Progress table grades are incorrect"

Problem: inconsistency with how the grades were calculated/compared, the progress percentages ones were correct but because the actual data ones were wrongly calculated for module level, it seemed as if the percentages are wrong.

Solution: refactored to have only one consistent way 😄

Note the problem was because it was comparing 7.0 to 60 (as passing grade), same for 1.0 vs 10 (for pass/fail ones) and giving off failing grade interestingly enough which made it harder to find 😅

Another bug was that when calculating the percentage scores, it divided by the total rows instead of the rows that belonged to the assignment (or module) depending on the progress view. So if there were 3 assignments with 10 scores each it would divide (#passing scores in assignment 1)/30 instead of (#passing scores in assignment 1)/(#scores in assignment 1)

Demonstration:

Before: wrong grades in module level

Before: correct grades in assignment level (also stats are the same with module level if you notice)

After: correct grades in module level

After: correct grades in assignment level (pass/fail case demonstration)

Closes #137 (closed)