feat(Activity): support for CUSTOM_STATUS activity type (#3353)

* feat: support for custom status in activity

* nit(typings): order properties

src/structures/Presence.js

@@ -3,6 +3,7 @@
 const Util = require('../util/Util');
 const ActivityFlags = require('../util/ActivityFlags');
 const { ActivityTypes } = require('../util/Constants');
+const Emoji = require('./Emoji');
 
 /**
  * Activity sent in a message.
@@ -205,6 +206,18 @@ class Activity {
      * @type {Readonly<ActivityFlags>}
      */
     this.flags = new ActivityFlags(data.flags).freeze();
+
+    /**
+     * Emoji for a custom activity
+     * @type {?Emoji}
+     */
+    this.emoji = data.emoji ? new Emoji(presence.client, data.emoji) : null;
+
+    /**
+     * Creation date of the activity
+     * @type {number}
+     */
+    this.createdTimestamp = new Date(data.created_at).getTime();
   }
 
   /**
@@ -221,6 +234,15 @@ class Activity {
     );
   }
 
+  /**
+   * The time the activity was created at
+   * @type {Date}
+   * @readonly
+   */
+  get createdAt() {
+    return new Date(this.createdTimestamp);
+  }
+
   /**
    * When concatenated with a string, this automatically returns the activities' name instead of the Activity object.
    * @returns {string}