Make TlsStream public and remote_addr accessible

[ousado]

Make TlsStream public and remote_addr accessible - useful if access to the remote address is required in make_service_fn, service_fn or connection/request handlers:

let make_svc = make_service_fn(|stream:&TlsStream| {
    let remote_addr = stream.remote_addr();
    async move {
        Ok::<_, io::Error>(service_fn(move |req| {
            handle_connection(req, remote_addr)
    }))
}

[ousado]

should have looked at the other TlsAcceptor and related PRs first.