mod_pubsub: Explicitly enable persistence by default to preserve behavior Since nodes were always persistent according to the XEP-0060 definition. Whether data is stored in memory or on disk was not what this setting was meant for.

util.pubsub: Handle absence of node data interface This is in preparation for fixing the behavior of 'persist_items', which was misunderstood at some point. In mod_pep it toggles between persistent storage and in-memory storage, while the correct behavior would be to toggle whether published items are stored at all or forgotten after being broadcast.

mod_pubsub: Remove publisher field when not exposing publisher The publisher is already there on the item when the broadcaster gets it, so it needs to do the opposite thing.

mod_pubsub: Normalize 'publisher' JID All the XEP-0060 examples have the publisher attribute set to a bare JID, but the text does allow it to be the full JID. Since mod_pubsub is more likely used for open nodes that anyone can subscribe to it makes sense to not leak the full JIDs. This is also disabled by defaults. In mod_pep on the other hand it might make sense to have the full JID since that data is more likely to be broadcast to contacts which are already somewhat trusted.

scansion tests: Enable 'expose_publisher' since we test for it

mod_pubsub: Respect 'expose publisher' setting in item retrieval

mod_pubsub: Fix inclusion of publisher (fixes #1399)

Merge 0.11->trunk

MUC: Fix logic for access to affiliation lists Fixes https://prosody.im/security/advisory_20210722/ Backs out 4d7b925652d9

MUC: Skip adding to history when it's set to zero Optimizes away all the processing on every message in case the end-result is zero history.