registry resource : patched async (still TODO queue) added scheduled refresh
* added (async) event based async resource update (but not used for now)
* patched work based async resource update : transaction etc. as well as test
* TODO still using default work queue because custom one blocks until end
   of test (transaction ? session ?)
* new feature : periodically scheduled refresh (download & parse) of Resources.
   Added refreshResources schedule (whose eventCategory is used as NXQL
   query criteria on ResourceDownloadInfos) & listener (which reinits rdi:url,
   which triggers redownload because changes are listened to by
   ResourceListener)