Evaluate switching from mocha to jest

[igorshapiro]

https://github.com/facebook/jest.

It seems however that jest does not support programmatic launch like mocha. It means we'll probably need to run it in a separate process, which will require test bootstrap refactoring

[rudovjan]

Took a look probably not worthy unless bigger change how we do DI and with bunch of refactoring.

jestjs/jest#2147 + others

Jest is not providing anything better than mocha. And mocha with globals (what Quadro is doing now) is actually almost same approach as jest.

Nothing prevents to add other tools what Jest is providing.