Moved DataElement to its own file

Moved the typescript DataElement class to its own file.
Signed-off-by: Robert Smith <smithrw@ornl.gov>

rse-renderer-client-test/frontend/src/data-element.ts

+/**
+ * Tasks:
+ * 
+ * *Move DataElement<T> to its ts file. It would be really nice to put this in the data structures project since it shadows a class there.
+ * *Add a unit test?
+ */
+
+export class DataElement<T> {
+    name: string;
+    description: string;
+    data!: T;
+
+    constructor() {
+        this.name = 'name';
+        this.description = 'description';
+    }    
+}
\ No newline at end of file

rse-renderer-client-test/frontend/src/renderer.ts

 import {css, customElement, html, LitElement, property} from 'lit-element';
 import '@vaadin/vaadin-text-field';
-
-
-/**
- * Tasks:
- * 
- * *Move DataElement<T> to its ts file. It would be really nice to put this in the data structures project since it shadows a class there.
- * *Add a unit test?
- */
-
-export class DataElement<T> {
-     name: string;
-     description: string;
-     data!: T;
- 
-     constructor() {
-         this.name = 'name';
-         this.description = 'description';
-     }    
-}
+import { DataElement } from './data-element'
 
 /**
  * Tasks: