test: add CTest to cmake to enable testing

[realstealthninja]

Description of Change

Testing

This pr enables testing of the algorithms in the repository
before we get to the stage of running tests on a CI. We will need to remove all
other code from every main function so that the only remaining code is a call to the test function.

for now this draft pull request shows how easy it is to enable testing.
adding it to the awesome CI will be as easy as adding
make test to a test step.

Checklist

• Added description of change
• Added file name matches File name guidelines
• Added tests and example, test must pass
• Added documentation so that the program is self-explanatory and educational - Doxygen guidelines
• Relevant documentation/comments is changed or added
• PR title follows semantic commit guidelines
• Search previous suggestions before making a new one, as yours may be a duplicate.
• I acknowledge that all my contributions will be made under the project's license.

Notes:

[github-actions]

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[realstealthninja]

@vil02 Do you think we should wait until all test cases pass, i.e. fix all the files?

[vil02]

@vil02 Do you think we should wait until all test cases pass, i.e. fix all the files?

In short: yes.

But the optimistic thing is that maybe one can work directory by directory, i.e. select one, let's say math, make all of the files there runnable (they cannot contain any std::cin, scanf or any other user input), modify the corresponding CMakelist.txt file to treat all of the cpp file as tests and merge this change.

Doing all at once is way too much.