Fix bug publish screenshot (#762)

[Preview this branch](https://cosmos-explorer-preview.azurewebsites.net/pull/762?feature.someFeatureFlagYouMightNeed=true)

The main change in this PR fixes the snapshot functionality in the Publish pane-related components. Because the code cell outputs are now rendered in their own iframes for security reasons, a single snapshot of the notebook is no longer possible: each cell output takes its own snapshot and the snapshots are collated on the main notebook snapshot.
- Move the snapshot functionality to notebook components: this removes the reference of the notebook DOM node that we must pass to the Publish pane via explorer.
- Add slice in the state and actions in notebook redux for notebook snapshot requests and result
- Add post robot message to take snapshots and receive results
- Add logic in `NotebookRenderer` to wait for all output snapshots done before taking the main one collating.
- Use `zustand` to share snapshot between Redux world and React world. This solves the issue of keeping the `PanelContainer` component generic, while being able to update its children (`PublishPanel` component) with the new snapshot.

Additional changes:
- Add `local()` in `@font-face` to check if font is already installed before downloading the font (must be done for Safari, but not Edge/Chrome)
- Add "Export output to image" menu item in notebook cell, since each cell output can take its own snapshot (which can be downloaded)
![image](https://user-images.githubusercontent.com/21954022/117454706-b5f16600-af46-11eb-8535-6bf99f3d9170.png)

src/Explorer/Notebook/NotebookManager.tsx

@@ -26,6 +26,7 @@ import { CopyNotebookPane } from "../Panes/CopyNotebookPane/CopyNotebookPane";
 import { PublishNotebookPane } from "../Panes/PublishNotebookPane/PublishNotebookPane";
 import { ResourceTreeAdapter } from "../Tree/ResourceTreeAdapter";
 import { NotebookContentProvider } from "./NotebookComponent/NotebookContentProvider";
+import { SnapshotRequest } from "./NotebookComponent/types";
 import { NotebookContainerClient } from "./NotebookContainerClient";
 import { NotebookContentClient } from "./NotebookContentClient";
 
@@ -112,11 +113,13 @@ export default class NotebookManager {
   public async openPublishNotebookPane(
     name: string,
     content: NotebookPaneContent,
-    parentDomElement: HTMLElement
+    notebookContentRef: string,
+    onTakeSnapshot: (request: SnapshotRequest) => void,
+    onClosePanel: () => void
   ): Promise<void> {
     const explorer = this.params.container;
     explorer.openSidePanel(
-      "New Collection",
+      "Publish Notebook",
       <PublishNotebookPane
         explorer={this.params.container}
         junoClient={this.junoClient}
@@ -125,8 +128,10 @@ export default class NotebookManager {
         name={name}
         author={getFullName()}
         notebookContent={content}
-        parentDomElement={parentDomElement}
-      />
+        notebookContentRef={notebookContentRef}
+        onTakeSnapshot={onTakeSnapshot}
+      />,
+      onClosePanel
     );
   }