feat(external-api) Add functions to query supported commands/events

modules/API/external/external_api.js

@@ -1191,6 +1191,24 @@ export default class JitsiMeetExternalAPI extends EventEmitter {
         return this._numberOfParticipants;
     }
 
+    /**
+     * Returns array of commands supported by executeCommand().
+     *
+     * @returns {Array<string>} Array of commands.
+     */
+    getSupportedCommands() {
+        return Object.keys(commands);
+    }
+
+    /**
+     * Returns array of events supported by addEventListener().
+     *
+     * @returns {Array<string>} Array of events.
+     */
+    getSupportedEvents() {
+        return Object.values(events);
+    }
+
     /**
      * Check if the video is available.
      *