[FA1.2] Verify FA1.2 camlCase, Edukera, and Dexter implementations
This MR introduces the formal FA1.2 standard and verifies three implementations:
- The Edukera FA1.2 contract originally written in Archetype
- The Dexter 2 FA1.2 liquidity ledger originally written in Ligo
- The camlCase FA1.2 contract originally written in Morley