Merge openbox-openrc and xfce-openrc into xfce-openbox-openrc

The packages in openbox-openrc and xfce-openrc were more or less the same except openbox or xfce on top; merging the configs reduces my burden of creating, testing, and uploading ISOs.

In the new ISO both Xfce and Openbox are present and configured; by default I think I will start Xfce, Openbox can be chosen by logging out and selecting it from the login manager.