j'ai écris la commande permettant d'obtenir le pourcentage d'utilisation de la lettre X et l'ai placé dans extract-line.sh

Ajout d'une question sur les fichiers binaires.

This part was not covered during the lecture but files were investigated instead.

- The palindrome exercise is a bit difficult in C, it was simply removed
- The prime number exercise has been transfered to C

Add the Swift part of the exam

See merge request outils-info/exam!1