ingestion: make "group" of attached documents easily configurable

Base_viewNewFileDialog/your_publication_section allows to easily suggest
a default publication section to the user, but the "group" was not so
easily customizable, it was just getting from document or user.

Introduce the same mechanism as for publication section, a type based
script that can be defined for each portal type.

bt5/erp5_ingestion/SkinTemplateItem/portal_skins/erp5_ingestion/Base_getPreferredAttachedDocumentGroup.py

+"""
+  Return the default group relative url to be added in the
+  document uploaded when attaching document using Base_viewNewFileDialog
+"""
+portal = context.getPortalObject()
+group = context.getProperty('group')
+if not group:
+  user = portal.portal_membership.getAuthenticatedMember().getUserValue()
+  if user is not None:
+    group = user.getGroup()
+
+return group

bt5/erp5_ingestion/SkinTemplateItem/portal_skins/erp5_ingestion/Base_getPreferredAttachedDocumentGroup.xml

+<?xml version="1.0"?>
+<ZopeData>
+  <record id="1" aka="AAAAAAAAAAE=">
+    <pickle>
+      <global name="PythonScript" module="Products.PythonScripts.PythonScript"/>
+    </pickle>
+    <pickle>
+      <dictionary>
+        <item>
+            <key> <string>Script_magic</string> </key>
+            <value> <int>3</int> </value>
+        </item>
+        <item>
+            <key> <string>_bind_names</string> </key>
+            <value>
+              <object>
+                <klass>
+                  <global name="NameAssignments" module="Shared.DC.Scripts.Bindings"/>
+                </klass>
+                <tuple/>
+                <state>
+                  <dictionary>
+                    <item>
+                        <key> <string>_asgns</string> </key>
+                        <value>
+                          <dictionary>
+                            <item>
+                                <key> <string>name_container</string> </key>
+                                <value> <string>container</string> </value>
+                            </item>
+                            <item>
+                                <key> <string>name_context</string> </key>
+                                <value> <string>context</string> </value>
+                            </item>
+                            <item>
+                                <key> <string>name_m_self</string> </key>
+                                <value> <string>script</string> </value>
+                            </item>
+                            <item>
+                                <key> <string>name_subpath</string> </key>
+                                <value> <string>traverse_subpath</string> </value>
+                            </item>
+                          </dictionary>
+                        </value>
+                    </item>
+                  </dictionary>
+                </state>
+              </object>
+            </value>
+        </item>
+        <item>
+            <key> <string>_params</string> </key>
+            <value> <string></string> </value>
+        </item>
+        <item>
+            <key> <string>id</string> </key>
+            <value> <string>Base_getPreferredAttachedDocumentGroup</string> </value>
+        </item>
+      </dictionary>
+    </pickle>
+  </record>
+</ZopeData>

bt5/erp5_ingestion/SkinTemplateItem/portal_skins/erp5_ingestion/Base_viewNewFileDialog/your_group.xml

@@ -116,7 +116,7 @@
       <dictionary>
         <item>
             <key> <string>_text</string> </key>
-            <value> <string>python: context.getProperty(\'group\') or context.getPortalObject().portal_membership.getAuthenticatedMember().getUserValue() is not None and here.getPortalObject().portal_membership.getAuthenticatedMember().getUserValue().getGroup() or \'\'</string> </value>
+            <value> <string>python: context.getTypeBasedMethod(\'getPreferredAttachedDocumentGroup\')()</string> </value>
         </item>
       </dictionary>
     </pickle>