[WIP] Fixed shading and moved endercore to a separate repo.

[Rover656]

Description

Moves endercore out to its own repo, brings it in over maven and takes shadowing out of this project completely, fixing the problem with duplicating registrate code.

Todo

• Setup the endercore repository
• Get endercore publishing to maven
• Setup maven properly in this project
• Final checks

Checklist:

• My code follows the style guidelines of this project (.editorconfig, most IDEs will use this for you)
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation

[Rover656]

Builds will fail due to unavailability of EnderCore over maven. This'll get fixed once maven publishing is setup on a new repo for EnderCore.

[Rover656]

Massively overcomplex compared to a new solution that should've taken 10 mins