Change the registry to use world UUIDs

[gecko10000]

Description

I have recently run into an issue where a world, when created quickly enough after deletion of a world with the same name, will not store data. I have tested this extensively and narrowed the issue down to this ticker code and this check for the world's existence. Since the ticker code only runs every half second, it does not remove the world from the registry until up to a Slimefun tick later and therefore causes issues in the constructor.

An easy way to recreate this issue is to delete a world and immediately create a new one with the same name.

Proposed changes

This PR changes the registry to use UUIDs instead of the world names themselves. This does not affect the storage location in files and therefore these are not breaking changes.

This may not be the ideal way to do it; it may be better to remove the world from the registry here instead.

Related Issues (if applicable)

No issue opened

Checklist

• I have fully tested the proposed changes and promise that they will not break everything into chaos.
• I have also tested the proposed changes in combination with various popular addons and can confirm my changes do not break them.
• I have made sure that the proposed changes do not break compatibility across the supported Minecraft versions (1.14.* - 1.19.*).
• I followed the existing code standards and didn't mess up the formatting.
• I did my best to add documentation to any public classes or methods I added.
• I have added Nonnull and Nullable annotations to my methods to indicate their behaviour for null values
• I added sufficient Unit Tests to cover my code.

[svr333]

This does look indeed like it isnt a breaking change and would still work with all worlds.
So in that case it looks good to me!

[J3fftw1]

im not sure how i closed this throught git.
I was updating his branch.