[SE-4445] Refactor the handbook's Table of Contents

This MR groups the related pages under a section title in the navigation bar of the handbook. With these changes it will be easy to navigate and find the relevant sections in the handbook easily.

JIRA tickets: https://tasks.opencraft.com/browse/SE-4445

Testing instructions:

  1. Verify the navigation section of the handbook groups only the relevant pages.




Edited by Sandeep Kumar Choudhary