use module container_file_write in lxc_guest

roles/lxc_guest/tasks/main.yaml

@@ -129,8 +129,11 @@
         var: request_output
         verbosity: 2
 
-    - name: set cert key
-      shell: lxc-attach -n {{ vm_name }} --clear-env -e -- bash -c "echo '{{ cert_key.result }}' > /etc/ssh/ssh_host_ed25519_key-cert.pub"
+    - name: Write certificate to container
+      container_file_write:
+        name: "{{ vm_name }}"
+        path: "/etc/ssh/ssh_host_ed25519_key-cert.pub"
+        text: "{{ cert_key.result }}"
       register: set_pub_key
   when: "cert_key_existance.rc != 0"