[WIP] Rename GUI and PostVis config file

Rename the Vadere GUI and PostVis config files. Especially, the GUI config file has a misleading name VadereTestingSuite.preferences.xml.

Before merging, fix following error:

Expand to see java.io.FileNotFoundException

15:42:07,490  INFO ActionCloseApplication:28 - closing application...
15:42:07,496  INFO ApplicationWriter:30 - saving preferences...
java.io.FileNotFoundException: /home/benedikt/Repos/Vadere/vadere/VadereGui/target/vadere-gui.jarconfig/postvisualization_config.properties (Datei oder Verzeichnis nicht gefunden)
        at java.base/java.io.FileOutputStream.open0(Native Method)
        at java.base/java.io.FileOutputStream.open(FileOutputStream.java:298)
        at java.base/java.io.FileOutputStream.(FileOutputStream.java:237)
        at java.base/java.io.FileOutputStream.(FileOutputStream.java:126)
        at org.vadere.gui.components.utils.Resources.save(Resources.java:106)
        at org.vadere.gui.projectview.utils.ApplicationWriter.savePreferences(ApplicationWriter.java:31)
        at org.vadere.gui.projectview.control.ActionAbstractSaveProject.savePreferences(ActionAbstractSaveProject.java:117)
        at org.vadere.gui.projectview.control.ActionCloseApplication.actionPerformed(ActionCloseApplication.java:35)
        at org.vadere.gui.projectview.view.ProjectView$1.windowClosing(ProjectView.java:354)
        at java.desktop/java.awt.AWTEventMulticaster.windowClosing(AWTEventMulticaster.java:357)
        at java.desktop/java.awt.Window.processWindowEvent(Window.java:2078)
        at java.desktop/javax.swing.JFrame.processWindowEvent(JFrame.java:298)
        at java.desktop/java.awt.Window.processEvent(Window.java:2037)
        at java.desktop/java.awt.Component.dispatchEventImpl(Component.java:5008)
        at java.desktop/java.awt.Container.dispatchEventImpl(Container.java:2321)
        at java.desktop/java.awt.Window.dispatchEventImpl(Window.java:2772)
        at java.desktop/java.awt.Component.dispatchEvent(Component.java:4840)
        at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:772)
        at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
        at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715)
        at java.base/java.security.AccessController.doPrivileged(Native Method)
        at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
        at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:95)
        at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:745)
        at java.desktop/java.awt.EventQueue$5.run(EventQueue.java:743)
        at java.base/java.security.AccessController.doPrivileged(Native Method)
        at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
        at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:742)
        at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
        at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
        at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
        at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
        at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
        at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)