Refactor: Insert opponentCard into PlayerRelation.getCard() and LocalPlayer.getCard()

[simonsasse]

Currently, there is a widget class called opponentCard, that creates a Card based on the state of the given opponent.

This functionality should be moved into the Friendship class and named getCard()

Another similar function should exist in the singleton class LocalPlayer which inherits from Player.

[akriese]

Just leaving this here ;)