Add StructureLib and BlockRenderer

[koolkrafter5]

"How do I build the next tier of the blood altar?" - a question asked by literally everybody
The solution:

Requires https://github.com/GTNewHorizons/StructureLib and https://github.com/GTNewHorizons/BlockRenderer6343.

The schematic item can also be used to autobuild the structure using blocks in the inventory when used on the altar. It has no recipe, so it will have to be given one in the pack if we want that to be available.

I also plan to add a ritual viewer handler to BM which will require these mods.