For creating aggregated views on one or multiple other Data Arrays

/reviewed-on klaus/wendelin!2

Data Bucket Stream is usefull when storing data from many small files

/reviewed-on klaus/wendelin!6

(cherry picked from commit 416502dc)

Conflicts:
	bt5/erp5_wendelin/DocumentTemplateItem/portal_components/document.erp5.IngestionPolicy.py
	bt5/erp5_wendelin/TestTemplateItem/portal_components/test.erp5.testWendelin.py

(cherry picked from commit 1ca48658)

This allows to set all kinds of arrow properties while keeping the main view simple.

The previous implementation did not support saving categories in view form.
It is better to use standard Base_edit in view forms and put actions which are other than "save"
into a dialog.