rails 32

@eac
 - return a proxy from self.foo
 - create on .create
 - enqueue on .deliver

classic will hook into this by sending the old deliver_ / create_ methods to it, so we should have a smooth transition

```

    alias_method :method_missing_without_deprecated, :method_missing

    # convert old create/deliver_foo to foo().deliver (.create is handled via action_mailer-enqueable)
    def method_missing(name, *args, &block)
      if match = /^(create|deliver)_([_a-z]\w*)/.match(name.to_s)
        method_missing_without_deprecated(match[2], *args, &block).send(match[1])
      else
        method_missing_without_deprecated(name, *args, &block)
      end
    end
```

for https://github.com/zendesk/zendesk/pull/8197