Add attributes to atomic, memset, one, oneview, packet, proxmox, and xenserver modules (#5958)

Add attributes to atomic, memset, one, oneview, packet, proxmox, and xenserver modules.

plugins/modules/packet_sshkey.py

@@ -16,6 +16,13 @@ description:
      - Create/delete an SSH key in Packet host.
      - API is documented at U(https://www.packet.net/help/api/#page:ssh-keys,header:ssh-keys-ssh-keys-post).
 author: "Tomas Karasek (@t0mk) <tom.to.the.k@gmail.com>"
+extends_documentation_fragment:
+  - community.general.attributes
+attributes:
+  check_mode:
+    support: none
+  diff_mode:
+    support: none
 options:
   state:
     description: