plugin XEP-0470: fix autocreate in `create_attachments_node`: Due to config check, `create_attachments_node` was failing when the target node was not already existing. However, this is the case when an item is published and `autocreate` is expected, thus the node is now created if not already existing and new `autocreate` argument is set.

[Desktop Entry]
Type=Application
Name=Libervia TUI (Primitivus)
Comment=console frontend for Libervia (XMPP)
Exec=libervia-tui
Icon=org.libervia.LiberviaTUI
Categories=Network;InstantMessaging;Chat;FileTransfer;RemoteAccess;
Keywords=xmpp;chat;messaging;im;file;sharing;communication;jabber;social;network;decentralization;console;