lib: connect/h2/h3 refactor

Refactoring of connection setup and happy eyeballing. Move
nghttp2. ngtcp2, quiche and msh3 into connection filters.

 - eyeballing cfilter that uses sub-filters for performing parallel connects
 - socket cfilter for all transport types, including QUIC
 - QUIC implementations in cfilter, can now participate in eyeballing
 - connection setup is more dynamic in order to adapt to what filter did
   really connect.  Relevant to see if a SSL filter needs to be added or
   if SSL has already been provided
 - HTTP/3 test cases similar to HTTP/2
 - multiuse of parallel transfers for HTTP/3, tested for ngtcp2 and quiche

 - Fix for data attach/detach in VTLS filters that could lead to crashes
   during parallel transfers.
 - Eliminating setup() methods in cfilters, no longer needed.
 - Improving Curl_conn_is_alive() to replace Curl_connalive() and
   integrated ssl alive checks into cfilter.
 - Adding CF_CNTRL_CONN_INFO_UPDATE to tell filters to update
   connection into and persist it at the easy handle.

 - Several more cfilter related cleanups and moves:
   - stream_weigth and dependency info is now wrapped in struct
     Curl_data_priority
   - Curl_data_priority members depend is available in HTTP2|HTTP3
   - Curl_data_priority members depend on NGHTTP2 support
   - handling init/reset/cleanup of priority part of url.c
   - data->state.priority same struct, but shallow copy for compares only

 - PROTOPT_STREAM has been removed
   - Curl_conn_is_mulitplex() now available to check on capability

 - Adding query method to connection filters.
   - ngtcp2+quiche: implementing query for max concurrent transfers.

 - Adding is_alive and keep_alive cfilter methods. Adding DATA_SETUP event.
   - setting keepalive timestamp on connect
   - DATA_SETUP is called after the connection has been completely
     setup (but may not connected yet) to allow filters to initialize
     data members they use.

 - there is no socket to be had with msh3, it is unclear how select
   shall work

 - manual test via "curl --http3 https://curl.se" fail with "empty
   reply from server".

 - Various socket/conn related cleanups:
   - Curl_socket is now Curl_socket_open and in cf-socket.c
   - Curl_closesocket is now Curl_socket_close and in cf-socket.c
   - Curl_ssl_use has been replaced with Cur_conn_is_ssl
   - Curl_conn_tcp_accepted_set has been split into
     Curl_conn_tcp_listen_set and Curl_conn_tcp_accepted_set
     with a clearer purpose

Closes #10141

lib/http2.h

@@ -40,44 +40,31 @@ void Curl_http2_ver(char *p, size_t len);
 
 const char *Curl_http2_strerror(uint32_t err);
 
-CURLcode Curl_http2_init(struct connectdata *conn);
-void Curl_http2_init_state(struct UrlState *state);
-void Curl_http2_init_userset(struct UserDefined *set);
 CURLcode Curl_http2_request_upgrade(struct dynbuf *req,
                                     struct Curl_easy *data);
-CURLcode Curl_http2_setup(struct Curl_easy *data, struct connectdata *conn);
-CURLcode Curl_http2_switched(struct Curl_easy *data,
-                             const char *ptr, size_t nread);
-/* called from http_setup_conn */
-void Curl_http2_setup_conn(struct connectdata *conn);
-void Curl_http2_setup_req(struct Curl_easy *data);
-void Curl_http2_done(struct Curl_easy *data, bool premature);
-CURLcode Curl_http2_done_sending(struct Curl_easy *data,
-                                 struct connectdata *conn);
-CURLcode Curl_http2_add_child(struct Curl_easy *parent,
-                              struct Curl_easy *child,
-                              bool exclusive);
-void Curl_http2_remove_child(struct Curl_easy *parent,
-                             struct Curl_easy *child);
-void Curl_http2_cleanup_dependencies(struct Curl_easy *data);
-CURLcode Curl_http2_stream_pause(struct Curl_easy *data, bool pause);
 
 /* returns true if the HTTP/2 stream error was HTTP_1_1_REQUIRED */
 bool Curl_h2_http_1_1_error(struct Curl_easy *data);
+
+bool Curl_conn_is_http2(const struct Curl_easy *data,
+                        const struct connectdata *conn,
+                        int sockindex);
+
+bool Curl_http2_may_switch(struct Curl_easy *data,
+                           struct connectdata *conn,
+                           int sockindex);
+
+CURLcode Curl_http2_switch(struct Curl_easy *data,
+                           struct connectdata *conn, int sockindex,
+                           const char *ptr, size_t nread);
+
 #else /* USE_NGHTTP2 */
+
+#define Curl_conn_is_http2(a,b,c) FALSE
+#define Curl_http2_may_switch(a,b,c) FALSE
+
 #define Curl_http2_request_upgrade(x,y) CURLE_UNSUPPORTED_PROTOCOL
-#define Curl_http2_setup(x,y) CURLE_UNSUPPORTED_PROTOCOL
-#define Curl_http2_switched(x,y,z) CURLE_UNSUPPORTED_PROTOCOL
-#define Curl_http2_setup_conn(x) Curl_nop_stmt
-#define Curl_http2_setup_req(x)
-#define Curl_http2_init_state(x)
-#define Curl_http2_init_userset(x)
-#define Curl_http2_done(x,y)
-#define Curl_http2_done_sending(x,y) (void)y
-#define Curl_http2_add_child(x, y, z)
-#define Curl_http2_remove_child(x, y)
-#define Curl_http2_cleanup_dependencies(x)
-#define Curl_http2_stream_pause(x, y)
+#define Curl_http2_switch(a,b,c,d,e) CURLE_UNSUPPORTED_PROTOCOL
 #define Curl_h2_http_1_1_error(x) 0
 #endif