Refactor the documentation

[folmos-at-orange]

• [x] The README.md should be a standard one: https://www.makeareadme.com/ for example
• [ ] ~~TODOs should be transformed in issues or discarded~~
• [x] Create a developer's documentation in the wiki
• [x] All internal readmes should be transformed to markdown.
• [ ] Have only one README (there are two currently the one at the root and another inside packaging).

[marcboulle]

Uniformiser le format et localisation de l'ensemble des readme du repo