BullsAndCowsNumber.cs refactor:

1. Loose Couple issue found:
- Not needed use of a Result object in TryToGuess. Modified to return an int array with [Bulls Matches, Cows Matches] instead.
- Renamed private Result TryToGuess to  private int[] GetBullsAndCowsMatches

2. Variables Scope and lifetime issues:
- class field Random rrr is removed as a class field, as it's used only in two methods - GetCheat() and GenerateRandomNumber(). Instead, we define an internal random generators in both methods.

- class field char[] getCheat removed as a class field and redefined in the GetCheat() method, as it's only scope is in that method.