(core) Show Grist video tour after welcome questions

Summary:
After the welcome questions are dismissed, a video tour modal will
now be displayed. The video tour is also accessible via a tool button
in the left panel of the home page, as well as a text button next to
the Examples & Templates header.

Test Plan: Browser tests.

Reviewers: dsagal

Reviewed By: dsagal

Subscribers: dsagal

Differential Revision: https://phab.getgrist.com/D3477

app/client/components/commandList.js

@@ -102,7 +102,17 @@ exports.groups = [{
       name: 'openWidgetConfiguration',
       keys: [],
       desc: 'Open Custom widget configuration screen',
-    }
+    },
+    {
+      name: 'leftPanelOpen',
+      keys: [],
+      desc: 'Shortcut to open the left panel',
+    },
+    {
+      name: 'videoTourToolsOpen',
+      keys: [],
+      desc: 'Shortcut to open video tour from home left panel',
+    },
   ]
 }, {
   group: 'Navigation',