Improve registering event values

[Efnilite]

Description

• Deprecates Getter
• Makes registering an event value require a Converter instead of a Getter
• Adds method for registering an event value without having to specify the time

Example
Before

EventValues.registerEventValue(WorldEvent.class, World.class, new Getter<World, WorldEvent>() {
		@Override
		@Nullable
		public World get(final WorldEvent e) {
			return e.getWorld();
		}
}, EventValues.TIME_NOW);

After

EventValues.registerEventValue(WorldEvent.class, World.class, WorldEvent::getWorld);

---

Target Minecraft Versions: any
Requirements: none
Related Issues: #5006

[sovdeeth]

related #5405

[APickledWalrus]

I might like to see Getter deprecated, and perhaps you could have it extend Function and just change the existing method signatures

[Efnilite]

I might like to see Getter deprecated, and perhaps you could have it extend Function and just change the existing method signatures

this PR was the beginning of my war against Getter. glad you agree :)

[Fusezion]

efy, told me to, I have no qualms about this, it's something I've been waiting for, makes event values not a pain

[Burbulinis]

love it need it like it very nice!

[sovdeeth]

Do you intend to finish updating BukkitEventValues?

[Moderocky]

Just to make sure this doesn't get merged before Sovde's comment gets a response.

[Efnilite]

Do you intend to finish updating BukkitEventValues?

It was mostly for example purposes. Idm though, should I or is it too prone to merge conflicts?