token-2022: Execute transfer hook during confidential transfer

[joncinque]

Problem

If a mint is configured with a transfer hook, the program is meant to be called during all transfers. This doesn't happen during confidential transfers though.

Summary of changes

The program changes are pretty simple: just execute the transfer hook, as in a normal transfer. This comes with a few other changes:

• b834e96 refactor some confidential transfer test helpers to be used in the transfer hook test
• 55f51c8 call the incorrect Transfer Hook: Off-chain and on-chain helpers are resolving keys incorrectly #6064 account resolver in token-client for all confidential transfer functions
• dc28301 featurize the processor changes, to avoid deploying them accidentally
• rename destination_token_account_info -> destination_account_info for consistency

The biggest issue is that we don't know the amount transferred when calling the hook. I decided to go with u64::MAX as a convention, rather than adding another instruction to the interface. Transfer hooks are complicated enough as is, so forcing programs to implement another instruction seems like a bad idea. Let me know if you have better ideas!

[samkim-crypto]

Sorry it took a while to catch up on some of the transfer hook interface. All the changes look fine to me. Thanks for fixing the variables names as well. I think the convention of using u64::MAX is reasonable to keep things as simple as possible.

[buffalojoec]

Looks good to me! You mentioned you'll want to rebase this once the PRs go in for fixing #6064, but that should be a pretty minimal change here.

Pull request has been modified.

[joncinque]

I added a new helper for this since resolve_extra_transfer_account_metas is deprecated, let me know how it looks!

[buffalojoec]

Lgtm, just some up-to-you nits!

Pull request has been modified.