Combine hud with gameplay

frontend/assets/Roboto-Black.ttf

frontend/assets/Roboto-Regular.ttf

frontend/assets/gameplay-skin.atlas

frontend/assets/gameplay-skin.json

frontend/assets/gameplay-skin.png

frontend/build.gradle

frontend/core/src/com/game/tankwars/ResourceManager.java

frontend/core/src/com/game/tankwars/TankWarsGame.java

...core/src/com/game/tankwars/controller/GameController.java

frontend/core/src/com/game/tankwars/model/Tank.java

frontend/core/src/com/game/tankwars/model/Terrain.java

frontend/core/src/com/game/tankwars/view/GameHud.java

frontend/core/src/com/game/tankwars/view/GameScreen.java

frontend/core/src/com/game/tankwars/view/LoginScreen.java