mod_pep: Remove use of RLU cache when persist_items was set to false This behavior came from some confusion over the meaning of persist_items. The correct behavior is that items are only stored when it is set to true. When set to false, the service becomes a "pure" publish-subscribe service, where items are forgotten immediately after broadcasting.

util.pubsub: Fix behavior of persist_items disabled When set to 'false' there is no need for a persistence interface at all, since items are not persisted after being broadcast. Had started wondering if maybe the behavior was wrong, after reading parts of XEP-0060 that pointed in that direction. Some discussion of this can be found in logs of xmpp:xsf@muc.xmpp.org?join from around 2021-07-20 Thanks to Ralph for confirming.

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