mod_firewall: Improve error when mark name contains invalid characters

mod_firewall: marks: Fix marking a user with no previous marks

mod_firewall: Update user marks to store instantly via map store The original approach was to keep marks in memory only, and persist them at shutdown. That saves I/O, at the cost of potentially losing marks on an unclean shutdown. This change persists marks instantly, which may have some performance overhead but should be more "correct". It also splits the marking/unmarking into an event which may be watched or even fired by other modules.

mod_firewall: Split some long lines [luacheck]

mod_firewall: Fix inverted logic of 'FROM FULL JID?'

mod_firewall: spam-blocking.pfw: Remove requirement for invites to have no body Some clients (e.g. Gajim) send a body, which I guess makes sense. The bare JID sender check should already make it hard to bypass this (i.e. a normal client putting muc#user into a normal chat message shouldn't bypass the usual message filters).

mod_firewall: scripts: spam-blocklists: Check sender and inviter of MUC invitations against blocklist

mod_firewall: scripts: spam-blocking.pfw: Add special handling for MUC invites

mod_firewall: Add 'FROM FULL JID?' condition

mod_firewall: README: Add some emphasis on the exact behaviour of TO FULL JID