Core needs a Lifecycle

[Furthen64]

Core enters "run" function when it boots up aand for now that has worked ok. Now I need to enable the whole game engine to restart, and restart fresh, restart with a specific map loaded, etc... all this requires me to restart core.

• [x] Core needs some kind of lifecycle structure
• [x] Create Classes used when returning from lifecycle() and run() so we know what happened

Toolbar functionalities:

• [x] usecase: User clicks on Exit Game
• [x] usecase: User clicks on Load Map
• [x] usecase: User clicks on New Map

[Furthen64]

Done