Update Readmes

Signed-off-by: Balthazar Rouberol <balthazar.rouberol@mapado.com>
Include a LICENSE.txt file

Signed-off-by: Balthazar Rouberol <balthazar.rouberol@mapado.com>
Release the extension as a single module

Signed-off-by: Balthazar Rouberol <balthazar.rouberol@mapado.com>