Resolve "Login screen setup (without backend)"

frontend/assets/Roboto-Regular.ttf

frontend/assets/badlogic.jpg

frontend/assets/main-menu-logout-button.png

frontend/assets/main-menu-welcome-box.png

frontend/assets/menu-background.png

frontend/assets/menu-button-2.png

frontend/assets/menu-button.png

frontend/assets/menu-textures.atlas

frontend/assets/menu-textures.json

frontend/assets/menu-textures.png

frontend/assets/menu-textures2.png

frontend/assets/tankwars-logo.png

frontend/build.gradle

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

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

...ore/src/com/game/tankwars/controller/LoginController.java

.../src/com/game/tankwars/controller/MainMenuController.java

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

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

frontend/desktop/src/com/game/tankwars/DesktopLauncher.java