mod_smacks: Clear resumption token from persistent storage on resumption

mod_smacks: Persist old counter values to storage This allows clients that try to resume a session after a server restart to at least know which of their pending outgoing stanzas were received and which need to be re-sent. This removes the limit on how many of those counters are kept, which should be fixed eventually.

mod_smacks: Remove now unused variable [luacheck]

mod_smacks: Remove unused event Since nothing uses it. Some equivalent functionality may return in the future.

mod_smacks: Fix typo

mod_smacks: Flag both sessions to prevent duplicating queue on resumption I have no idea what is going on in this code, which session is which? Something has one of the sessions as an upvalue which is where the filter checks for it.

mod_smacks: Increment a counter for each resumption Encountered what looks like a bug where after *many* resumptions, part of the queue was not acked.

mod_smacks: Back out 48f8fa6cea7b - back in a86ae74da96c again Maybe it works now with the session patching in the previous commit

mod_smacks: Patch various self-references on the resumed session The number of places where the session is an upvalue to its own methods is too high!

mod_smacks: Back out a86ae74da96c: Fixed one problem, caused another As per a86ae74da96c the 'session' object here is the wrong session, so the attempt to block stanzas from being added to the queue twice did not work causing something of a leak. Instead we have a leak of the previous session.