Use a shared mojmap codebase for simple shared NMS code

[me4502]

The Problem

Currently we have large amounts of NMS code that either could be shared or is shared, but it's duplicated per platform (and per adapter in the case of Paper).

A Solution

Having a "shared" NMS codebase that is based off an "as clean as possible" mojmap base would allow us to share some code here, significantly reducing duplication and maintenance burden of some parts of code.

Would also likely reduce the size of the Bukkit jar as there'd be less duplication between adapters.

Alternatives

No response

Anything Else?

No response