List of common pitfalls for TS devs

[MartinMinkov]

List of a few common pitfalls to document:

1. In-circuit randomness
2. Reading out values of field elements in provable code
   • Existing example: https://github.com/o1-labs/o1js/issues/224
3. Always try to compile methods and create proofs as a way of ensuring a base level of correctness (to debug)
4. Conditional branching
5. Inheritence with SmartContract