Deprecate `ask_*` options

[daavoo]

Though, another thing to note is that ask_* options are a bit of a legacy thing coming from paramiko's limitations, and asyncssh might be raising proper exceptions that would allow us to distinguish when we need to ask password or a passphrase. If you could confirm that, maybe we can just make ask_password and password obsolete and not add new options at all.

Originally posted by @efiop in #3 (comment)

[pmrowla]

This can be done by implementing the interactive methods in an asyncssh client subclass, see the scmrepo/dulwich implementation: treeverse/scmrepo#255 (comment)

[pmrowla]

#52 implements the interactive methods required for 2fa with sshd ChallengeResponseAuthentication /KbdInteractiveAuthentication but is not a complete enough implementation to deprecate the current password/passphrase prompts entirely

This would need testing with more sshd configs in the future before it's probably safe to drop the ask_* options