relay: add connection to remote (issue #2066)

Connection to remote:

- handshake: offer support for all supported hash algorithms
- network connect with a socket
- upgrade to websocket and authenticate with remote (password/TOTP)
- check websocket response
- get list of buffers (not used yet)

Note: connection to remote with TLS or a proxy is not yet supported.

src/plugins/relay/api/relay-api-msg.c

@@ -172,7 +172,7 @@ relay_api_msg_send_json_internal (struct t_relay_client *client,
             string = cJSON_PrintUnformatted (json);
             num_bytes = relay_client_send (
                 client,
-                RELAY_CLIENT_MSG_STANDARD,
+                RELAY_MSG_STANDARD,
                 string,
                 (string) ? strlen (string) : 0,
                 NULL);  /* raw_message */

src/plugins/relay/api/remote/relay-remote-network.h

@@ -0,0 +1,26 @@
+/*
+ * Copyright (C) 2024 Sébastien Helleu <flashcode@flashtux.org>
+ *
+ * This file is part of WeeChat, the extensible chat client.
+ *
+ * WeeChat is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * WeeChat is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with WeeChat.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef WEECHAT_PLUGIN_RELAY_REMOTE_NETWORK_H
+#define WEECHAT_PLUGIN_RELAY_REMOTE_NETWORK_H
+
+extern int relay_remote_network_connect (struct t_relay_remote *remote);
+extern void relay_remote_network_disconnect (struct t_relay_remote *remote);
+
+#endif /* WEECHAT_PLUGIN_RELAY_REMOTE_NETWORK_H */