Different Double Slabs

This release is compatible with all versions 1.20.0 and up!*

*The only caveat is that the resource pack won't automatically have support for any new slabs added after 1.21.0, so message me on Discord reminding me to add them! (@owehttamy)

Changes:

• Added full support for all slabs in Supplementaries

Thanks @peow. on Discord!

• Added full support for all slabs in Stone Expansion

Thanks @peow. on Discord!

• Removed remnants of code from another project