xep-0092: make it possible to ask servers or components for software

This adds the new `/serversoftware` command.

```
/software user@domain.org/resource
/serversoftware domain.org
```

Fix https://github.com/profanity-im/profanity/issues/1338

src/command/cmd_defs.c

@@ -2433,6 +2433,23 @@ static struct cmd_t command_defs[] =
             { "on|off", "Enable or disable slashguard." })
         CMD_NOEXAMPLES
     },
+
+    { "/serversoftware",
+        parse_args, 1, 1, NULL,
+        CMD_NOSUBFUNCS
+        CMD_MAINFUNC(cmd_serversoftware)
+        CMD_TAGS(
+            CMD_TAG_DISCOVERY)
+        CMD_SYN(
+            "/serversoftware <domain>")
+        CMD_DESC(
+            "Find server or component software version information.")
+        CMD_ARGS(
+            { "<domain>", "The jid of your server or component." })
+        CMD_EXAMPLES(
+            "/software valhalla.edda",
+            "/software xmpp.vanaheimr.edda")
+    }
 };
 
 static GHashTable *search_index;

src/command/cmd_funcs.c

@@ -3521,6 +3521,25 @@ cmd_software(ProfWin *window, const char *const command, gchar **args)
     return TRUE;
 }
 
+gboolean
+cmd_serversoftware(ProfWin *window, const char *const command, gchar **args)
+{
+    jabber_conn_status_t conn_status = connection_get_status();
+
+    if (conn_status != JABBER_CONNECTED) {
+        cons_show("You are not currently connected.");
+        return TRUE;
+    }
+
+    if (args[0]) {
+        iq_send_software_version(args[0]);
+    } else {
+        cons_show("You must provide a jid to the /serversoftware command.");
+    }
+
+    return TRUE;
+}
+
 gboolean
 cmd_join(ProfWin *window, const char *const command, gchar **args)
 {

src/command/cmd_funcs.h

@@ -231,4 +231,5 @@ gboolean cmd_os(ProfWin *window, const char *const command, gchar **args);
 gboolean cmd_correction(ProfWin *window, const char *const command, gchar **args);
 gboolean cmd_correct(ProfWin *window, const char *const command, gchar **args);
 gboolean cmd_slashguard(ProfWin *window, const char *const command, gchar **args);
+gboolean cmd_serversoftware(ProfWin *window, const char *const command, gchar **args);
 #endif