Simplify stylesheet application

PlayWall/src/main/java/de/tobias/playpad/PlayPadImpl.java

PlayWall/src/main/java/de/tobias/playpad/PlayPadMain.java

...in/java/de/tobias/playpad/design/ModernDesignHandler.java

...ava/de/tobias/playpad/design/ModernDesignHandlerImpl.java

...ypad/layout/desktop/DesktopMenuToolbarViewController.java

...a/de/tobias/playpad/pad/listener/PadPositionListener.java

.../de/tobias/playpad/viewcontroller/AuthViewController.java

.../de/tobias/playpad/viewcontroller/dialog/AboutDialog.java

...pad/viewcontroller/dialog/ModernPluginViewController.java

...tobias/playpad/viewcontroller/dialog/PathMatchDialog.java

...aypad/viewcontroller/dialog/PlayoutLogViewController.java

.../de/tobias/playpad/viewcontroller/dialog/PrintDialog.java

.../playpad/viewcontroller/dialog/ProfileViewController.java

...aypad/viewcontroller/dialog/profile/NewProfileDialog.java

...ad/viewcontroller/dialog/profile/ProfileChooseDialog.java

...ad/viewcontroller/dialog/project/ProjectExportDialog.java

...ad/viewcontroller/dialog/project/ProjectImportDialog.java

...d/viewcontroller/dialog/project/ProjectManagerDialog.java

...aypad/viewcontroller/dialog/project/ProjectNewDialog.java

...obias/playpad/viewcontroller/main/MainViewController.java