This task is a follow up of https://developer.trustedfirmware.org/T639

This task is the result of the TF-M Workshop aimed at improving the user experience. It proposes a new more user friendly layout.

The components required for this stage are:

• Propose and discuss with the community the documentation contribution guidelines.
• Restructure the documentation in accordance to the Workshop's plan. A more explicit and easier to navigate layout, with contextual categorization of content.
• Make it easier for third party tools and services to build the documentation.
• Easier way to capture release information and changelogs

Content should not not be focus of first stage of improvements.