[ENHANCEMENT] xtd - Creation of the website

[gammasoft71]

xtd - Creation of the website

Enhancement

Creation of the the website.

Description

Creation of the website on GitHub with Docusaurus.

• create branch 'docs'
• Integration of existing markdown documentation with Docusaurus
• Add latest 'Reference guide'
• Add 0.1.0 'Reference guide'
• Put on line
• Deploy with GitHub action
• Update side bar position for all pages
• Update latest 'Reference guide' with Github action

Remarks

Later, it would be interesting to integrate the 'References Guide' in the website.
There could be several 'References Guide' (one per version).
This would imply to be able to generate the documentation with the github action and to be able to get the generated documentation in the github repo.