migrator: Also migrate host/non-user archive data Needed for things like mod_http_file_share

migrator: Refactor out individual item migrator for code deduplication

migrator: Include --options in usage info

migrator: Reuse earlier usage text

migrator: Customise cli argument parsing (--help, --verbose) Previously -v etc would do nothing and --config without argument would not have worked correctly.

util.startup: Allow supplying an argument parsing settings The 'prosody' global is not global this early so there was no way to override the process type field or argument parsing settings from outside, e.g. from the migrator.

util.prosodyctl.check: Parameterize replacement instructions This ought to make it easier to translate in the future. And easier to reword, now!

util.prosodyctl.check: Move word to ease future translations Recent experience with translations in the context of Snikket highlighted that sentences spread across concatenated strings like this makes the experience less than pleasant for translators. We don't have translation yet, but it is a future goal and why not? The duplication can be solved with a parameterized function for the common cases.

util.prosodyctl.check: Use same wording about 'daemonize' and 'no_daemonize' Why would they use different wording?

mod_bookmarks: Add option for disabling upgrade of legacy bookmarks Might be nice to reduce amount of things happening on connect once all users has upgraded