Add Art of Code to Courses (#7572)

* Add new course

* Fixed alphabetical ordering

* Update free-courses-en.md

Provided changes as suggested.

* Update free-courses-en.md

Fix linting alphabetical order.

* Update free-courses-en.md

Fix linting error; blank line

Co-authored-by: Tom <t.baten@sigmax.nl>

courses/free-courses-en.md

@@ -830,6 +830,7 @@
 * [Introduction to Quantum Computing and Quantum Hardware](https://qiskit.org/learn/intro-qc-qh) - Qiskit
 * [Introduction to Reinforcement Learning with David Silver](https://deepmind.com/learning-resources/-introduction-reinforcement-learning-david-silver) - David Silver
 * [MIT Numerical Methods (2014)](http://www.iitg.ernet.in/kartha/CE601-14/CourseSchedule.htm)
+* [The Art of Code - Dylan Beattie](https://www.youtube.com/watch?v=6avJHaC3C2U) - Dylan Beattie
 
 
 ### .NET