Adds stalactite ore placing override API

[YannickMG]

The intent is to allow the core mod (or any other mod) to specify which ores should be in the stalactites by providing a method to place that stalactite's blocks.

This is an alternative to the method used in #36.

Thanks to Minepolz320 for the original idea.

[github-actions]

Warning: 2 uncommitted changes
#42

[Gordon-Frohman]

There's one thing I don't really like about this method: you can't really tweak the rarity of the stalactite you're generating, plus you're not really adding a new stalactite, you're just replacing an existing one. I would rather add an option to add new stalactites, that would've compete for generation with vanilla ones. I guess I'll have to do it in my PR)

[Gordon-Frohman]

You can check my version out in #44

[Gordon-Frohman]

Did you check how it works with GT ores? Because I'm afraid that it may cause issues similar to those I got

[YannickMG]

In draft pending requirements.