Dominoes

Changes:

• Add "doubles", made by placing a second domino on the opposite corner of a placed corner domino
• Doubles can "fork" domino collapse chains, but only in one direction
• Doubles drop two dominoes when broken

Full Changelog: https://github.com/sisby-folk/dominoes/compare/0.2.0+fabric-1.21.8...0.3.0+fabric-1.21.8