Include the old exercises from the co-learning and resources repositories

[aoloe]

• [ ] https://github.com/opentechschool-zurich/cpp-co-learning/tree/master/20-min-projects
• [ ] https://github.com/opentechschool-zurich/py-co-learning/tree/master/20-min-projects
• [ ] https://github.com/opentechschool-zurich/resources/tree/master/15-min-projects/ale