feat(table): Expose currently rendered data from the datasource.

In order to give programmatic access to the data that is currently being rendered in the table, we should expose the renderedData BehaviourSubject.

Fixes #497

components/table/src/table-data-source.ts

@@ -113,6 +113,9 @@ export class DtTableDataSource<T> extends DataSource<T> {
   private _renderChangesSubscription = Subscription.EMPTY;
   private _searchChangeSubscription = Subscription.EMPTY;
 
+  /** Public stream emitting render data to the table */
+  renderData = this._renderData.asObservable();
+
   /** Array of data that should be rendered by the table, where each object represents one row. */
   get data(): T[] {
     return this._data.value;