feat(ViewerLocalFileData): Add drag/drop to load DICOM files in the Viewer at /local (#644)

src/connectedComponents/ViewerLocalFileData.css

@@ -0,0 +1,15 @@
+.drag-drop-instructions {
+  width: 100%;
+  height: 100%;
+  display: flex;
+  justify-content: center;
+  align-items: center;
+}
+
+.drag-drop-instructions h3 {
+  color: var(--active-color);
+}
+
+.drag-drop-instructions h4 {
+  color: var(--text-secondary-color);
+}