Post-upload import step notifications added.

Temporary PROGRESS_EVENTs added to mark the ends of the current 5 import steps
following file upload.
Switch order of import step notifications to reflect steps in ManagedImportRequestI.
Re-organise file upload events.
Fix second conflict
Adding back deleted subclass to fix build.
Refactor PROGRESS_EVENT to improve log output.
Remove unused events.
Merge pull request #693 from ximenesuk/fs-import-notifications

Fs import notifications