util.error: Add well-known field 'code' in error templates Intended to be for HTTP-ish numeric status codes

mod_register_limits: Use util.error for managing rejection reasons

mod_register_ibr: Allow registartion rejection reason as util.error object

Backed out changeset 64ddcbc9a328 as it would prevent communicating with valid remote JIDs that aren't valid under STRINGPREP / Unicode 3.2

MUC: Enforce strict resourceprep on nicknames (bye bye robot face)

core.stanza_router: Do strict jidprep on c2s Be conservative in what you let your clients send, be liberal in what you let in via s2s. Being strict on s2s leads to interop problems and poor experiences, ie users being ejected from MUCs if something invalid enters. By starting with tightening up input into the network, we may be able to gradually approach a point where no invalid JIDs are allowed.

util.encodings: Strictly verify that the 'strict' *prep argument is a boolean This is to prevent mistakes like nodeprep(username:gsub("a","b")) from unintentionally invoking strict mode.

util.jid: Add a 'strict' flag for jidprep calls

util.encodings: Optional strict flag to stringprep

util.pubsub, pubsub.lib and tests: Add text to precondition-not-met error (fixes #1455)