Add Jest as a test engine

[MaximDevoir]

Add support for the Jest engine and enable Mocha and Jest tests to work seamlessly together.

[MaximDevoir]

Differentiate Jest and Mocha tests by the an infix.

Mocha filename format would be name.spec.ext

Jest filename format would be name.test.ext

[MaximDevoir]

I think we should support Jest out-of-the-box and drop support for Mocha. Right now, supporting the Mocha and Jest test engines is too much to maintain.

If there is a demand for supporting Mocha as a test engine, then we can look into re-adding and maintaining another test engine.

I still think we should follow the filenaming conventions mentioned above to future-proof Mocha integration into CNA.

In the meantime, users who prefer to use Mocha can add mocha to their project's dependencies and replace their test script from nom-scripts test to point to the mocha binary.