adds minimal example of CTest functionality

This merge request adds a few examples of the relevant "add_test" CMake call, but just simple bash commands. Some are broken by design, some are meant to work.

Draft because I want to fix the python code to use an actual "throw".

08_ctest/broken_test/CMakeLists.txt

+add_test(
+    NAME broken_test
+    COMMAND python -c "print('this test is broken by design'); raise RuntimeError('This is an error-throwing Python code')")