feat(Question Tracker): Correct answer tracker

[fingerson]

• Adds a question tracker to the current session.

• Implemented as a Singleton.

• Counts right and wrong answers.

• Usage:

• • Reset counters by calling the method startQuiz(questionAmount: Int = 0)
  • Add result to tracker by calling the method func addResult(answerStatus: Bool)
  • Read values directly from variables questionAmount, correctAnswers, wrongAnswers, all of them are Ints.

• Closes #30