qm-guest-exec: add page (#9133)

* qm-guest-exec: add page

* Added specified changes

* Update pages/linux/qm-guest-exec.md

* Update pages/linux/qm-guest-exec.md

* Update pages/linux/qm-guest-exec.md

* Update pages/linux/qm-guest-exec.md


* Apply suggestions from code review

pages/linux/qm-guest-exec.md

@@ -0,0 +1,20 @@
+# qm guest exec
+
+> Execute a specific command via a guest agent.
+> More information: <https://pve.proxmox.com/pve-docs/qm.1.html>.
+
+- Execute a specific command via a guest agent:
+
+`qm guest exec {{vm_id}} {{command}} {{arg1 arg2 ...}}`
+
+- Execute a specific command via a guest agent asynchronously:
+
+`qm guest exec {{vm_id}} {{arg1 arg2 ...}} --synchronous 0`
+
+- Execute a specific command via a guest agent with a specified timeout of 10 seconds:
+
+`qm guest exec {{vm_id}} {{arg1 arg2 ...}} --timeout {{10}}`
+
+- Execute a specific command via a guest agent and forward input from STDIN until EOF to the guest agent:
+
+`qm guest exec {{vm_id}} {{arg1 arg2 ...}} --pass-stdin 1`