Integrate Menu entry "New Systems 2023" better into tree

Information on new hardware is not on the overview page for hardware (https://doc.zih.tu-dresden.de/jobs_and_resources/hardware_overview/), but on a separate page (https://doc.zih.tu-dresden.de/jobs_and_resources/hardware_overview_2023/), which is confusing (which page is currently valid?) and contradicts our goal to provide a consistent and up to date documentation. See also https://doc.zih.tu-dresden.de/contrib/howto_contribute/:

Our goal is to provide a general, consistent and up to date documentation.

Also, the pages do not follow content rules, e. g. Writing Style:

Use "You can/should ..." instead of "Users can/should ..."