Fix file downloads from notebooks container (#196)

* Fix file downloads from notebooks container

* Add downloading message

src/Utils/BlobUtils.ts

@@ -0,0 +1,17 @@
+export const stringToBlob = (data: string, contentType: string, sliceSize = 512): Blob => {
+  const byteArrays = [];
+
+  for (let offset = 0; offset < data.length; offset += sliceSize) {
+    const slice = data.slice(offset, offset + sliceSize);
+
+    const byteNumbers = new Array(slice.length);
+    for (let i = 0; i < slice.length; i++) {
+      byteNumbers[i] = slice.charCodeAt(i);
+    }
+
+    const byteArray = new Uint8Array(byteNumbers);
+    byteArrays.push(byteArray);
+  }
+
+  return new Blob(byteArrays, { type: contentType });
+};