Reworked ArchiveRequest jobs lifecycles.
Changed the lifecycle of the ArchiveRequest to handle the various combinations of several jobs and their respective success/failures. Most notably, the request now holds a reportdecided boolan, which is set when decing to report. This happens when failing to archive one copy (first failure), or when all copies are transferred (success for all copies). Added support for in-mount retries. On falure, the job will be requeued (with a chance to pick it up again) in the same session if sane session retries are not exceeded. Otherwise, the job is left owned by the session, to be picked up by the garbage collector at tape unmount. Made disk reporter generic, dealing with both success and failure. Improved mount policy support fir queueing. Expanded information avaible in popped element from archive queues. Added optional parameters to ArchiveRequest::asyncUpdateJobOwner() to cover various cases. Updated the archive job statuses. Clarified naming of functions (transfer/report failure instead of bare \"failure\"). Updated garbage collector for new archive job statuses. Added support for report retries and batch reporting in the scheduler database. Updated obsolete wording in MigrationReportPacker log messages and error counts.