[build] Create basic unit tests

[WilliamTjonndal]

Description

Write unit tests for most classes. Some of the tests will require new mock classes.

Proposed Solution

Screenshots

Prerequisite Issues

Additional Context

Mock classes that were required:

• MockPresenter

Task Checklist

Model unit tests

Entities

• BoardSquareFactoryTest
• PieceFactoryTest

Singletons

• GameSettingsTest
• GameTest
• LobbyTest

Presenter unit tests

• PresenterManagerTest

View unit tests

• Lwjgl3LauncherTest