token-2022/memo-transfer: add a Pinocchio version #785

tokens/token-2022/memo-transfer ships only an Anchor version. This proposes a Pinocchio version, matching the other Token-2022 extension examples that already have one (immutable-owner, default-account-state, transfer-fee, …).

The program creates a Token-2022 token account and enables the MemoTransfer extension on it. The test checks the extension is set, that an incoming transfer without a memo is rejected, and that the same transfer succeeds when preceded by a memo.

Implementation is ready in #700.