(core) Polish tutorial popups

Summary:
Includes the following changes:
 *  Adds "Click to expand" hover tooltip to all images
 *  Adds support for minimize/maximize by double clicking tutorial popup header
 *  Add New menu (and all other popups) should now persist when user moves tutorial popup
 *  Preserves scrollbar position when minimizing and maximizing tutorial popup
 *  Formula cell editor (and other elements) should now be stacked under tutorial

Test Plan: Browser and manual tests.

Reviewers: jarek

Reviewed By: jarek

Differential Revision: https://phab.getgrist.com/D3864

app/client/ui/HomeLeftPane.ts

@@ -217,7 +217,7 @@ function workspaceMenu(home: HomeModel, ws: Workspace, renaming: Observable<Work
   function deleteWorkspace() {
     confirmModal(t("Delete {{workspace}} and all included documents?", {workspace: ws.name}), t("Delete"),
       () => home.deleteWorkspace(ws.id, false),
-      t("Workspace will be moved to Trash."));
+      {explanation: t("Workspace will be moved to Trash.")});
   }
 
   async function manageWorkspaceUsers() {