Seared Ladder (Backport)

Backports the seared ladder from tconstruct 1.16+. The seared ladder is a block that makes it super easy to get in or out of a smeltery! Useful for people like me who regularly fall into their smelteries, or who need blood for a craft and find it awkward to get back out.

Credits:
-all code and textures by me
-block models, language support, and original idea by tconstruct