interface: API crate(s) for token2022

[joncinque]

Recreated from solana-labs/solana-program-library#6466

Currently if you want to build a token2022 instruction, parse an account etc, you import the whole program.

Problem 1: this forces you to compile the whole program and bring in dependencies that are only used in internal program code.
Problem 2: token2022 is a huge program with multiple responsibilities so we probably need multiple API crates. For example, only some users of token2022 would need to use anything involving the zk token sdk.

Solution:

Rip a bunch of code out of the program crate and into various API crates. Re-export in spl-token-2022 for backwards compatibility