Replaced local GameState and GameStateManager with ZED version
Using GameStateManager to manage the game's lifecycle

|SOURCE|
[Common/GameplayEvents::GameplayInputListener]
* This class handles converting events into game-specific data
[Common/GameplayGameState]
* Handles the gameplay game state, pops itself off the stack once the game has
  exited
* The escape key is used to exit the state
[Common/Game]
* The GameStateManager from ZED is used to manage the game's lifecycle
* Keyboard state is obtained and sent to the event router when executing
* Removed the now-useless Update and Render member functions
* Tied m_Running to the state of the GameStateManager