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/NotebookComponent/actions.ts

@@ -1,6 +1,7 @@
 import { CellId } from "@nteract/commutable";
 import { ContentRef } from "@nteract/core";
 import { Action } from "../../../Shared/Telemetry/TelemetryConstants";
+import { SnapshotFragment, SnapshotRequest } from "./types";
 
 export const CLOSE_NOTEBOOK = "CLOSE_NOTEBOOK";
 export interface CloseNotebookAction {
@@ -85,21 +86,68 @@ export const traceNotebookTelemetry = (payload: {
   };
 };
 
-export const UPDATE_NOTEBOOK_PARENT_DOM_ELTS = "UPDATE_NOTEBOOK_PARENT_DOM_ELTS";
-export interface UpdateNotebookParentDomEltAction {
-  type: "UPDATE_NOTEBOOK_PARENT_DOM_ELTS";
+export const STORE_CELL_OUTPUT_SNAPSHOT = "STORE_CELL_OUTPUT_SNAPSHOT";
+export interface StoreCellOutputSnapshotAction {
+  type: "STORE_CELL_OUTPUT_SNAPSHOT";
   payload: {
-    contentRef: ContentRef;
-    parentElt: HTMLElement;
+    cellId: string;
+    snapshot: SnapshotFragment;
   };
 }
 
-export const UpdateNotebookParentDomElt = (payload: {
-  contentRef: ContentRef;
-  parentElt: HTMLElement;
-}): UpdateNotebookParentDomEltAction => {
+export const storeCellOutputSnapshot = (payload: {
+  cellId: string;
+  snapshot: SnapshotFragment;
+}): StoreCellOutputSnapshotAction => {
   return {
-    type: UPDATE_NOTEBOOK_PARENT_DOM_ELTS,
+    type: STORE_CELL_OUTPUT_SNAPSHOT,
+    payload,
+  };
+};
+
+export const STORE_NOTEBOOK_SNAPSHOT = "STORE_NOTEBOOK_SNAPSHOT";
+export interface StoreNotebookSnapshotAction {
+  type: "STORE_NOTEBOOK_SNAPSHOT";
+  payload: {
+    imageSrc: string;
+    requestId: string;
+  };
+}
+
+export const storeNotebookSnapshot = (payload: {
+  imageSrc: string;
+  requestId: string;
+}): StoreNotebookSnapshotAction => {
+  return {
+    type: STORE_NOTEBOOK_SNAPSHOT,
+    payload,
+  };
+};
+
+export const TAKE_NOTEBOOK_SNAPSHOT = "TAKE_NOTEBOOK_SNAPSHOT";
+export interface TakeNotebookSnapshotAction {
+  type: "TAKE_NOTEBOOK_SNAPSHOT";
+  payload: SnapshotRequest;
+}
+
+export const takeNotebookSnapshot = (payload: SnapshotRequest): TakeNotebookSnapshotAction => {
+  return {
+    type: TAKE_NOTEBOOK_SNAPSHOT,
+    payload,
+  };
+};
+
+export const NOTEBOOK_SNAPSHOT_ERROR = "NOTEBOOK_SNAPSHOT_ERROR";
+export interface NotebookSnapshotErrorAction {
+  type: "NOTEBOOK_SNAPSHOT_ERROR";
+  payload: {
+    error: string;
+  };
+}
+
+export const notebookSnapshotError = (payload: { error: string }): NotebookSnapshotErrorAction => {
+  return {
+    type: NOTEBOOK_SNAPSHOT_ERROR,
     payload,
   };
 };