Describe the solution you'd like

Ideally, a configuration option to whitelist specific biomes for the generation of each ore.

Why would you like this to be implemented?

Many of us use mods like Biomes O' Plenty, and on a server especially using Metallurgy can give a lot of variety to material choice, but for some of us, we'd like to be able to control where the ore spawns a bit more than just pure frequency. A whitelist for specific biomes the ores could spawn in would give us more control over this, for example being able to make mithril only able to spawn in extreme hills in vanilla, or Alps in BoP

Additional context (optional)

Add any other context or screenshots about the feature request here.