Remove MetaUtils

[Protonull]

This primarily removes MetaUtils (#793) and modernises ItemUtils. The bulk of the changes in this PR is the renaming of, for example, setDisplayName to setLegacyDisplayName so that setComponentDisplayName can just be setDisplayName.

The "legacy" methods still use ItemMeta instead of using data components because I cannot guarantee that LegacyComponentSerializer serialises components the same way that ItemMeta does, since ItemMeta uses CraftChatMessage internally.

I've also removed the varargs variants of the "set" and "add" lore methods: there were (and still are) far too many sequential addLore calls adding only a single line each time. If people are forced to do List.of() then maybe they'll collect it all into a single call... one can hope.

I've also added getCustomData and editCustomData and updated ItemExchange to use them: the current code is adequate but brittle and inefficient.

This also updates the DebugWand hack to use CivModCore's CustomItem interface. I want to move as many things away from the ItemUtils#areItemsSimilar (and consequently ChatUtils#areComponentsEqual) as possible.