Replace GeyserRelocationMixinExtension with a build time script

[rtm516]

Currently GeyserRelocationMixinExtension is used to get around the relocated classes in Geyser and mixing into them. The way it works isn't ideal and should be replaced with a build time gradle action that uses ASM to remap the mixin calls at compile time.

https://github.com/GeyserMC/Hydraulic/blob/301a831a23881b1c89e80ddfdcf4d6b77725e815/fabric/src/main/java/org/geysermc/hydraulic/fabric/GeyserRelocationMixinExtension.java

This is open for anyone to fix.