Create a Fluid Flow API

[OroArmor]

This copies from https://github.com/FabricMC/fabric/pulls/1402, however, as I am the authors of said PRs, I allow my code to be added to QSL.

The testmod is a good example of how to add a new fluid flow event.

Questions to be asked:

• [ ] Should this API be part of a larger Fluid API?
• [ ] Should the event holding be restructured to something else?

Before this is merged, I would like to merge in a game test api to ensure vanilla behavior remains and to have a more effective test than currently having to go into a world to view the change.

[OroArmor]

Thats a good point, ill have the direction be a parameter

[oliviathevampire]

This needs to be updated to newest code + maybe can be made into an REA?

[OroArmor]

This can't easily be made into a REA, but yeah I can update it.

[OroArmor]

And by easily I mean it shouldn't. It's an event, not a property because there are too many variables