transport: introduce `git_transport_smart_remote_connect_options` 6fc6eeb66c40310086c8f059cae41de69ad4c6da removed `git_transport_smart_proxy_option`, and there was nothing added to replace it. That made it hard for custom transports / smart subtransports to know what remote connect options to use (e.g. proxy options). This change introduces `git_transport_smart_remote_connect_options` to replace it.