Updated the user guide with new article + updated old content (#16955)

- more details on rate at which messages are imported from Gmail
- Settings -> Release deprecated to Settings -> Updates => this leads to
updating the file title, file name and the navigation files
- Support & Documentation accessible via Settings and no longer the nav
bar
- updated features out of the lab
- no more integration page
- added a new article with step by step on how to notify a teammate of a
note to review

docs.json is updated only for the English part

---------

Co-authored-by: github-actions <github-actions@twenty.com>

packages/twenty-docs/user-guide/dashboards/overview.mdx

@@ -8,6 +8,10 @@ image: /images/user-guide/reporting/pie-chart.png
   <img src="/images/user-guide/reporting/pie-chart.png" alt="Dashboards" />
 </Frame>
 
+<Note>
+Dashboards are currently in beta. Activate them under **Settings → Updates → Early Access**.
+</Note>
+
 ## Understanding Dashboards
 
 Dashboards in Twenty provide a visual way to track your key performance metrics and gain insights from your CRM data.