Add loot condition for farm drops and EMI integration for generatable loot tables

[OffsetMonkey538]

Would allow datapacks to add custom drops only available from the mob farm, or prohibit some drops from appearing in one.
Example:
Zombies can drop iron armor in the farm. They normally can't, because they'd need to spawn with armor and iirc that's not possible in the farm.
Iron Golems don't drop iron in farms, but instead drop iron nuggets, otherwise it'd be too op.

I'll also add this as part of this issue:
EMI integration for displaying what items can be generated from the compact mob farm.

Actually let's do it like this instead:

• Loot Condition for farm drops #7
• Datagen provider for entity tier list #8
• Builtin packs for some mobs #9
• EMI integration for generatable loot #10

[OffsetMonkey538]

Actually let's do it like this instead:

1. Loot Condition for farm drops
2. Datagen provider for entity tier list
3. Builtin packs for some mobs
4. EMI integration for generatable loot