Started translating library/os.po (python#1531)

Co-authored-by: Christophe Nanteuil <35002064+christopheNan@users.noreply.github.com>
Co-authored-by: Mathieu Dupuy <deronnax@gmail.com>
Co-authored-by: Mathieu Dupuy <mathieu.dupuy@critizr.com>

Author: 4 people