add sorting for gallery

pdb-js/src/app/gallery-view/gallery-view.component.html

@@ -1,4 +1,27 @@
-<div id="gallery" class="card-grid-300">
+<div
+  *ngIf="show" 
+  id="gallery-filters">
+    
+    <mat-form-field class="pdb-form-wide">
+      <mat-label>Sort By:</mat-label>
+      <mat-select [(value)]="sortBy">
+        <mat-option value="NAME">name</mat-option>
+        <mat-option value="MAX_VALUE">max value</mat-option>
+        <mat-option value="AVERAGE">average</mat-option>
+        <mat-option value="VALUES">#values</mat-option>
+        <mat-option value="PLOTTED_VALUES">#plotted values</mat-option>
+      </mat-select>
+    </mat-form-field>
+    
+    <div class="pdb-form-icon-small">
+      <pdb-image-toggle images="{{ascDescImages}}" (valueChanged)="sortOrderChanged($event)"></pdb-image-toggle>
+    </div>
+    
+  </div>
+<div
+  *ngIf="show" 
+  id="gallery" 
+  class="card-grid-300">
   <pdb-gallery-item-view
     *ngFor="let galleryItem of galleryItems" [data]="galleryItem">
   </pdb-gallery-item-view>