Add support for CTest (better IDE compatibility)

[DarkWanderer]

• Each test fixture will be run in separate process (if one crashes, others still run)
• IDEs support CTest (Visual Studio, IDEA, CLion, ...)
• Automatic registration of tests by adding an .sqf file
• Same framework for sqf tests and C++ tests in future

[X39]

Hey, first of all:
Thanks for the PR.

Given you modified the CMakeLists.txt, may i ask whether you could also integrate (and might finish) theese changes into https://github.com/SQFvm/runtime/tree/cmake/cleanup ?

thanks in advance.

Will leave the PR open for today to allow you to respond :)