templates/layout: Add a switch to toggle full width rendering
Add a switch in the top left part of the UI in order to toggle full width rendering of web application content.
This can be useful for high resolution screens or to extend the viewport width for source code rendering.
The full width rendering state is also saved in browser local storage in order to restore it on each web application page load.
Closes #2456 (closed)
Test Plan
New cypress tests have been added.
Migrated from D3295 (view on Phabricator)