README: Added content.
Fixes wet-boew/wet-boew#6180.
[README] Added French description for the legacy repository.
Merge pull request #3 from thomasgohard/desc-corrections

Added description for the wet-boew-legacy repository
Merge pull request #4 from wet-boew/add-desc-legacy-readme

Added description for the wet-boew-legacy repository
[README] Added .md extension.
Merge pull request #5 from thomasgohard/fix-readme-filename

[README] Added .md extension.