I'm wondering if there is even a point to Flowable at this point. Half of the blocks inheriting from it do not break instantly, or have some other modification to tool requirements.
This has been a pain point for a long time due to the misleading nature of the name "level". It's also confusing when trying to do things like getting the XP level of the player or such, and also does not translate well to other languages.
This transition was already executed on the UI some time ago (language strings) and now it's time for the same change to occur on the API.
This will burn a lot of plugins, but they'll acclimatize. Despite the scary size of this PR, there isn't actually so many changes to make. Most of this came from renaming `Position->getLevel()` to `Position->getWorld()`, or cosmetic changes like changing variable names or doc comments.
this is not remotely a complete implementation, it's just here to make PM aware of these states so that world conversion can be handled correctly. A full implementation will come later.
Any blocks added in this fashion should be marked with a //TODO so future maintainers can find which blocks need work.
The reason this uses a trait is because `self` refers to the including class in a trait, which offers a small amount of automatic type safety.
If we had templates or generics, this would be a generic class instead.
past me was full of shit, because blockReplace is the same as blockClicked when we click a single slab top/bottom to make a double slab, and the logic is identical to the below block with that in mind.
