Add documentation for work item two column view

What does this MR do and why?

Add documentation for work item two column view

Behind work_items_mvc_2 FF

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #415077 (closed)