feat(WelcomeScreen): welcome screens (#5490)

Co-authored-by: Jan <66554238+vaporox@users.noreply.github.com>
Co-authored-by: izexi <43889168+izexi@users.noreply.github.com>
Co-authored-by: SpaceEEC <spaceeec@yahoo.com>
Co-authored-by: Vlad Frangu <kingdgrizzle@gmail.com>

src/structures/InviteGuild.js

@@ -0,0 +1,23 @@
+'use strict';
+
+const AnonymousGuild = require('./AnonymousGuild');
+const WelcomeScreen = require('./WelcomeScreen');
+
+/**
+ * Represents a guild received from an invite, includes welcome screen data if available.
+ * @extends {AnonymousGuild}
+ */
+class InviteGuild extends AnonymousGuild {
+  constructor(client, data) {
+    super(client, data);
+
+    /**
+     * The welcome screen for this invite guild
+     * @type {?WelcomeScreen}
+     */
+    this.welcomeScreen =
+      typeof data.welcome_screen !== 'undefined' ? new WelcomeScreen(this, data.welcome_screen) : null;
+  }
+}
+
+module.exports = InviteGuild;