Remove page on Power9

All content is already availble on ZIH systems overview page!

If someone finds time, a separate page can be added later on.

requested review from @mflehmig--tu-dresden.de

assigned to @mflehmig--tu-dresden.de

added 1 commit

• cd32bd8e - Adjust links

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merged

mentioned in commit 9a035183

Resolve #87 (closed)