Make the home page pretty

[stevepiercy]

Links of affected pages in Plone Documentation, if any.

https://6.docs.plone.org/

Description

The home page is not great. For inspiration, see:

• https://numpy.org/doc/stable/
• https://pydata-sphinx-theme.readthedocs.io/en/stable/

We can use Sphinx Design to have a card-based layout.

We currently have no User Guide. See #1611 for the plan.

We have solid "Contributing guide" and "Get started", and the beginning of both "Developer guide" and "Conceptual guides".

We need a new page for "Reference guide" that includes links to any reference material, including plone.api and Plone REST API.

[rajatverma311201]

I want to do this task Could you please tell me how to run this project and make changes do i have to run make command only ? or where can i get the guidelines

[stevepiercy]

@rajatverma311201 https://6.docs.plone.org/contributing/documentation/