... this tool is used to update categories from spreadsheet

Uses graph editor component from DREAM simulation project http://dream-simulation.eu/

This editor is in early stage; it supports edition of business paths from business process and edition of workflow layout in DCWorkflow.

Known problems / TODO:
 - DCWorkflow editor only saves the graph layout and does not allow designing the workflow
 - DCWorkflow graph has to be enabled in history tab for history visualisation
 - rendering of fields in the property edition dialog is extremely slow
 - mixin_promise.js have to be merged. Other TODO's in test.js and jsplumb.js. Generally speaking, this javascript code is poor quality

For the new GroupedMessage class in commit
da234001, I renamed 'obj' to 'object'
at the last minute and I missed 2 occurrences.

The problem with callMethodOnObjectList is that when an object can't be
processed, all other objects of the same group fail without any chance to
be retried separately.

Grouping is configurable with usual CMFActivity parameters in new 'group_kw'
parameter, to avoid any conflict with catalog parameters (**kw).
'packet_size' and 'activity_count' are still accepted for backward
compatibility.

The recent API change was not enough.
A grouping method may need more information: in particular, the dummy grouping
method must be fixed to change user.

This moves much duplicated code to main()
and _ZodbTestComponentBootstrapOnly is changed to also search for BT in
subfolders, like in ERP5TypeTestCaseMixin._getBTPathAndIdList