Notebooks Gallery (#59)

* Initial commit

* Address PR comments

* Move notebook related stuff to NotebookManager and dynamically load it

* Add New gallery callout and other UI tweaks

* Update test snapshot

src/Explorer/Controls/NotebookGallery/Cards/GalleryCardComponent.test.tsx

@@ -1,15 +1,32 @@
-import React from "react";
 import { shallow } from "enzyme";
+import React from "react";
 import { GalleryCardComponent, GalleryCardComponentProps } from "./GalleryCardComponent";
 
 describe("GalleryCardComponent", () => {
   it("renders", () => {
     const props: GalleryCardComponentProps = {
-      name: "mycard",
-      url: "url",
-      notebookMetadata: undefined,
-      // eslint-disable-next-line @typescript-eslint/no-empty-function
-      onClick: () => {}
+      data: {
+        id: "id",
+        name: "name",
+        description: "description",
+        author: "author",
+        thumbnailUrl: "thumbnailUrl",
+        created: "created",
+        gitSha: "gitSha",
+        tags: ["tag"],
+        isSample: false,
+        downloads: 0,
+        favorites: 0,
+        views: 0
+      },
+      isFavorite: false,
+      showDelete: true,
+      onClick: undefined,
+      onTagClick: undefined,
+      onFavoriteClick: undefined,
+      onUnfavoriteClick: undefined,
+      onDownloadClick: undefined,
+      onDeleteClick: undefined
     };
 
     const wrapper = shallow(<GalleryCardComponent {...props} />);