cf: replace the method get_host with query

Connection filters had a method `get_host()` which had not really been
documented. Since then, the cf had the `query()` method added. Replace
the separate get_host with query.

Add `CF_QUERY_HOST_PORT` as query to connection filters to retrieve
which remote hostname and port the filter (or its sub-filter) is talking
to. The query is implemented by HTTP and SOCKS filters, all others pass
it through.

Add `Curl_conn_get_current_host()` to retrieve the remote host and port
for a connection. During connect, this will return the host the
connection is talking to right now. Before/After connect, this will
return `conn->host.name`.

This is used by SASL authentication.

Closes #17419

lib/cf-https-connect.c

@@ -562,7 +562,6 @@ struct Curl_cftype Curl_cft_http_connect = {
   cf_hc_connect,
   cf_hc_close,
   cf_hc_shutdown,
-  Curl_cf_def_get_host,
   cf_hc_adjust_pollset,
   cf_hc_data_pending,
   Curl_cf_def_send,