Re-implement the event generator as a new-style plugin - Mct4552 (#4620)

Updates Event Generator to ES6 classes and current API.

Co-authored-by: Andrew Henry <akhenry@gmail.com>
Co-authored-by: John Hill <john.c.hill@nasa.gov>

example/eventGenerator/plugin.js

@@ -0,0 +1,42 @@
+/*****************************************************************************
+ * Open MCT, Copyright (c) 2014-2022, United States Government
+ * as represented by the Administrator of the National Aeronautics and Space
+ * Administration. All rights reserved.
+ *
+ * Open MCT is licensed under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * http://www.apache.org/licenses/LICENSE-2.0.
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ *
+ * Open MCT includes source code licensed under additional open source
+ * licenses. See the Open Source Licenses file (LICENSES.md) included with
+ * this source code distribution or the Licensing information page available
+ * at runtime from the About dialog for additional information.
+ *****************************************************************************/
+import EventTelmetryProvider from './EventTelemetryProvider';
+import EventMetadataProvider from './EventMetadataProvider';
+
+export default function EventGeneratorPlugin(options) {
+    return function install(openmct) {
+        openmct.types.addType("eventGenerator", {
+            name: "Event Message Generator",
+            description: "For development use. Creates sample event message data that mimics a live data stream.",
+            cssClass: "icon-generator-events",
+            creatable: true,
+            initialize: function (object) {
+                object.telemetry = {
+                    duration: 5
+                };
+            }
+        });
+        openmct.telemetry.addProvider(new EventTelmetryProvider());
+        openmct.telemetry.addProvider(new EventMetadataProvider());
+
+    };
+}