kubectl-exec: add page (#17651)

Co-authored-by: Machiavelli <[email protected]>
Co-authored-by: Dylan <[email protected]>

Author: 3 people

pages/common/kubectl-exec.md

@@ -0,0 +1,8 @@
+# kubectl exec
+
+> Execute a command in a container.
+> More information: <https://kubernetes.io/docs/reference/generated/kubectl/kubectl-commands#exec>.
+
+- Open Bash in a pod, using the first container by default:
+
+`kubectl exec {{pod_name}} {{-it|--stdin --tty]}} -- bash`