[Appendix] - Add links to exercise resources and theoretical content websites

[braboj]

Discussed in https://github.com/braboj/tutorial-python/discussions/24

^{Originally posted by **Vasc01** September 15, 2023} - Links to websites with exercise problems related to the topics in the book - Links to websites with expanded explanations on the topics in the book. For example https://realpython.com.

[braboj]

Please sort out the best of these links and add them to the documentation. Use ChatGPT or a similar tool to create additional tasks and exercises. Each chapter shall have a folder with dedicated exercises. It is also possible to integrate the task questions into the official python guide.

https://www.w3resource.com/python-exercises/python-basic-exercises.php https://pynative.com/python-exercises-with-solutions https://www.w3schools.com/python/python_exercises.asp https://www.practicepython.org/ https://www.geeksforgeeks.org/python-exercises-practice-questions-and-solutions/ https://exercism.org/tracks/python/exercises https://edabit.com/challenges/python3 https://pythonbasics.org/exercises https://www.dataquest.io/blog/python-practice https://github.com/zhiwehu/Python-programming-exercises/blob/master/100%2B%20Python%20challenging%20programming%20exercises.txt