Add seperate rx/vn leaderboards

[Lekuruu]

A lot of people have requested to separate rx/vn leaderboards entirely, and I agree on that as well. At first I thought, making the pp system balanced enough would work, but that does not seem to be the case. To not completely restructure the way, the server works right now, I've come up with a new solution.
My Idea is to still combine rx & vn scores for pp ranks, but also making separate leaderboard for rx and vn at the same time. The rx/vn rank will get displayed on their profile if they choose so in the settings. Based on user feedback, I may or may not implement this in the future.

[kanaarima]

I think having separate ranks (Unified/VN/RX/AP) show in user profile page is enough.
Unified leaderboard can work with a balanced pp system and adjustments to score (which is mostly done right now) IMO