[Feature] More intuitive score sorting

[3plestar]

So right now when you sort by scores it seems to only take in account the highest score of all difficulties of a single song. So when you have a lot of scores in different difficulties, the sorting seems almost random.
I think it would be more intuitive to have songs be sorted by score seperately between different difficulties

Here is a demonstration of what I mean.

how scores are sorted now:
Novice      | Advance          | Exhaust
song 1: 800 | song 1: 999      | song 1: no score
song 2: 900 | song 2: no score | song 2: 700
song 3: 710 | song 3: 870      | song 3: 600


what I would expect:
Novice      | Advance          | Exhaust
song 2: 900 | song 1: 999      | song 2: 700
song 1: 800 | song 3: 870      | song 3: 600
song 3: 710 | song 2: no score | song 1: no score