plugin OXPS, XEP-0060: indicate which items were e2ee:

the new `encryption` key is added to `getItems` metadata if items were e2ee, it contains a
map from item ID to encryption metadata.

rel  380

sat/plugins/plugin_sec_oxps.py

@@ -736,6 +736,7 @@ class PubsubEncryption:
                 decrypted_elt = xml_tools.parse(decrypted)
                 item.children.clear()
                 item.addChild(decrypted_elt)
+                extra.setdefault("encrypted", {})[item["id"]] = {"type": NS_OXPS}
 
     async def _message_received_trigger(
         self,

sat/plugins/plugin_xep_0060.py

@@ -854,6 +854,9 @@ class XEP_0060(object):
                     # normally we have a strict equality here but XEP-0059 states
                     # that index MAY be approximative, so just in case…
                     metadata["complete"] = index + len(items) >= count
+        # encrypted metadata can be added by plugins in XEP-0060_items trigger
+        if "encrypted" in extra:
+            metadata["encrypted"] = extra["encrypted"]
 
         return (items, metadata)