Better explanation on the usage of docs/content folder

[tang-mm]

The current directory structure places the starter pack documentation under docs/content directory, and the main index page in the docs/ level.

.. toctree::
   :hidden:
   :maxdepth: 2

   Set up the documentation </content/set-up>
   /content/customise
   /content/rtd
   /content/update
   /content/automatic_checks
   /content/contributing

However, when creating new documentation projects from this repository, there is no explanation of the content folder and how users should organize their own documentation files. If users follow the practices in the existing folder, it results in generating a content/ segment in all the documentation pages:

• Current result: <domain>/docs/content/tutorial
• Expected result: <domain>/docs/tutorial

A clearer guidance is needed on how to organize documentation files.