Doc: add page for cluster power9, rename page for Julia

doc.zih.tu-dresden.de/docs/jobs_and_resources/sd_flex.md → doc.zih.tu-dresden.de/docs/jobs_and_resources/julia.md

-# HPE Superdome Flex
+# SMP System Julia
 
 The HPE Superdome Flex is a large shared memory node. It is especially well suited for data
 intensive application scenarios, for example to process extremely large data sets completely in main

doc.zih.tu-dresden.de/docs/jobs_and_resources/power9.md

+# GPU Cluster Power9
+

doc.zih.tu-dresden.de/mkdocs.yml

@@ -105,7 +105,8 @@ nav:
       - CPU Custer Romeo: jobs_and_resources/romeo.md
       - NVMe Storage: jobs_and_resources/nvme_storage.md
       - GPU Cluster Alpha Centauri: jobs_and_resources/alpha_centauri.md
-      - HPE Superdome Flex: jobs_and_resources/sd_flex.md
+      - SMP System Julia: jobs_and_resources/julia.md
+      - GPU System Power9: jobs_and_resources/power9.md
       - NVIDIA Arm HPC Developer Kit: jobs_and_resources/arm_hpc_devkit.md
     - Running Jobs:
       - Batch System Slurm: jobs_and_resources/slurm.md