erp5_calendar: xml format changes only
erp5_calendar: migrate Documents to portal_components
erp5_calendar : move Group Calendar Assignment to a separate module

This allows to define specific security setting and workflow for Group Calendar Assignments. Before
they were inside Group Calendars. Now a Group Calendar Assignment use the specialise Base
Category to specify the corresponding Group Calendar.
erp5_calendar: add interaction workflow to update catalog values

When a Group Calendar or a Group Presence Period is updated, it's necessary
to update related Group Assignment stock catalog data since values are dependent.
ERP5/PresencePeriod : rename _getDatePeriodList to _getDatePeriodDataList

Not only returns start and stop dates, but also quantity defined
on presence periods. This make it possible to set 3 hours availability
in a time range of 10 hours.
testCalendar: partially update test to take into account group assignments