qm-guest-cmd: add page (#9001)

pages/linux/qm-guest-cmd.md

@@ -0,0 +1,8 @@
+# qm guest cmd
+
+> Execute QEMU Guest Agent commands.
+> More information: <https://pve.proxmox.com/pve-docs/qm.1.html>.
+
+- Execute a specific QEMU Guest Agent command:
+
+`qm guest cmd {{vmid}} {{fsfreeze-freeze|fsfreeze-status|fsfreeze-thaw|fstrim|get-fsinfo|get-host-name|get-memory-block-info|get-memory-blocks|get-osinfo|get-time|get-timezone|get-users|get-vcpus|info|network-get-interfaces|ping|shutdown|suspend-disk|suspend-hybrid|suspend-ram}}`