Eradicate internal usages of new $class

[dktapps]

Problem description

Dynamic new is an anti-feature. It makes it difficult to do static analysis, usage searches, and also puts implicit requirements on constructors to follow a particular signature.

new $class is basically reflection and comes with all of the problems of using reflection. It needs to go away.

The following things still use dynamic new and need to be changed:

• TileFactory
• Block->writeStateToWorld() (to create new tiles)
• World generators (this might be a bit complicated to address due to threading)
• PlayerCreationEvent and general player construction

Proposed solution

Closures should be used instead. We did this with EntityFactory and with WorldProviderManager. It's a lot more flexible, fully statically analysable, allows extra parameters to be provided by the callback, and also allows the callback to do extra logic if need be.

Alternative solutions or workarounds

No response

Related issues

#6418 uses this anti-feature in new code
#3473 also affects PlayerCreationEvent, though not clear if getting rid of it is yet feasible
#6556 affects generators