Remove ScoreV2 as a rankable mod.

[RealistikDash]

Since the rewrite (or even earlier), score V2 has been allowed on the leaderboards. This is a major oversight due to its radical changes to the scoring system, which are incompatible with all other mods. This causes major discrepancies within score leaderboards.

[7ez]

i agree

[lenforiee]

looking good, approved!