Support any kind of `LeafEntry` for showing loot tables, not just `ItemEntry`s

[Antikyth]

I think you can use LeafEntry#generateLoot to get the stacks from a LeafEntry, considering it takes any Consumer<ItemStack>.

In my mod I add my own LeafEntry to have some more control over how I create the item stacks, but my entries do not show up in EMI Loot.

[fzzyhmstrs]

There would be no deterministic way for me to do this. Loot conditions and functions exist for providing fine tuned control

Also, EMI Loot currently parses 6 types of LootEntry, not just ItemEntry. (4 or 5 of which, even in vanilla, would not produce deterministic results if generateLoot was used)

That isn't to say I couldn't find some way to accommodate. Some fallback parsing that provides a "disclaimer condition" to the user that EMI Loot doesn't know for sure what the results should be.