Move request-specific description to GraphControl class
Split error report generation into separate method

- Keep default error generation using response parameters in CmdControl
- Overload create_error_report() in Chgrp and Delete commands to handle MIF exceptions
Show Activities panel with new errors
Fix merge conflict resolution bugs
Failed chgrp/delete MIF has 'REFRESH' data
Check hasattr(rsp, 'constraints') each time
Add 'omero.group' to lib.doSubmit() for chgrp target. See #10908
Chgrp to target Dataset. Fails for 2-image MIF. See #10908
Order controls according to mock-up.
Check if the file has to be uploaded after scanning.
Modify error handling of failure during scanning.
Upload method review, do no wait for import to complete.
Use button instead of label for cancel action.
Remove "Show thumbnails" option (see #10890)
Display result as soon as import is complete (see #10981)

No longer wait for thumbnails or plate to be loaded.
Fix loading of folder w/o valid candidates (see #10985)
Fix cancellation of files (see #10984)

Cancel after scanning a folder, cancelling files directly.
Cancel during folder scanning (see #10984)
Modify layout to match mockups.
Minor adjustment to workflow.