* update media / emoji cleaner funcs to use new paging package, check for same returned maxID
* fix other calls of getattachments and getmojis not using paging
* use alternative order-by function
* [bugfix] process account delete side effects in serial, not in parallel
* StartWorkers / StartNoopWorkers for tests
* undo testrig trace logging
* log errors instead of immediately returning
* update typeconverter to use state structure
* deinterface the typeutils.TypeConverter -> typeutils.Converter
* finish copying over old type converter code comments
* fix cherry-pick merge issues, fix tests pointing to old typeutils interface type still
