(core) Add behavioral and coaching call popups

Summary:
Adds a new category of popups that are shown dynamically when
certain parts of the UI are first rendered, and a free coaching
call popup that's shown to users on their site home page.

Test Plan: Browser tests.

Reviewers: jarek

Reviewed By: jarek

Differential Revision: https://phab.getgrist.com/D3706

app/client/components/RawDataPage.ts

@@ -42,6 +42,7 @@ export class RawDataPage extends Disposable {
 
   public buildDom() {
     return cssContainer(
+      dom('div', this._gristDoc.behavioralPrompts.attachTip('rawDataPage', {hideArrow: true})),
       dom('div',
         dom.create(DataTables, this._gristDoc),
         dom.create(DocumentUsage, this._gristDoc.docPageModel),