Introduce React Testing Library & Initial Test Of Game Scenario

[jacketattack]

Goal: Automatically know when we break expected behavior of a blackjack game

Acceptance Criteria

• Introduce react testing library as a dependency of the game
• Add a test file app.test.tsx that will cover testing different game scenarios with components rendered
• Add a test for the following scenario
  1. dealer is dealt 7 + 10 (7 is showing)
  2. player is dealt two kings (for 20 total)
  3. assert on visibility of hands in dealer and player
  4. click on 'stand' button
  5. assert that dealer shows 17 and does not hit
  6. assert on game showing player won the game