core: define Domain_getPriceCalculationOperandDict

This disable price lookup on domains, because it errors and because the
meaning is not clear.

It errors because Domains are MetaResources, so they are subclass of
Resource and they inherit the price lookup mechanism, which does not
work on domains because of their different `getRelativeUrl` implementation.

product/ERP5/bootstrap/erp5_core/SkinTemplateItem/portal_skins/erp5_core/Domain_getPriceCalculationOperandDict.py

+"""Domain does not lookup price.
+"""
+return default if default else {'price': None}

product/ERP5/bootstrap/erp5_core/SkinTemplateItem/portal_skins/erp5_core/Domain_getPriceCalculationOperandDict.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>default=None, movement=None, **kw</string> </value>
+        </item>
+        <item>
+            <key> <string>id</string> </key>
+            <value> <string>Domain_getPriceCalculationOperandDict</string> </value>
+        </item>
+      </dictionary>
+    </pickle>
+  </record>
+</ZopeData>