Incorporated strict validation in many schemas

[Vessel9817]

This is a continuation of #6191. As reviewal has begun there, I will continue to push changes here in order to prevent the review from not having enough time to catch up on all the changes.

Once again, to ease review, commits should be split to change one schema at a time, when possible. Larger changes should be split into multiple commits or merged in a separate PR.

[madskristensen]

This has a merge conflict.

[Vessel9817]

Thanks

[Vessel9817]

minecraft-*.json may be using additionalProperties inappropriately, meaning to use "properties": { "additionalProperties": { ... } } instead of "properties": { ... }. Additional tests are needed.

[Vessel9817]

Seems odd that minecraft-template-pool.json defines a processors property that, when an object, only contains a processors property. #2699 doesn't contain a schema reference, so I'll see what I can dig up.

[Vessel9817]

Nevermind, seems OK.

• Top-level reference
• Processor list reference

[Vessel9817]

additionalProperties-properties usage is also intended, corresponding to an NBT compound.

• Item modifier reference
• pack.mcmeta reference
• Predicate reference