pveperf: add page (#7212)

pages/common/pveperf.md

@@ -0,0 +1,8 @@
+# pveperf
+
+> A benchmarking tool in Proxmox Server. Gather CPU and hard disk performance data for the hard disk.
+> More information: <https://pve.proxmox.com/pve-docs/pveperf.1.html>.
+
+- Show CPU and hard disk performance data for the hard disk mounted at `/`:
+
+`pveperf`