erp5configurator: ConfiguratorItemMixin should not inherit Base class. Because of this wrong inheritance, configurator item classes did not work as Folder.

This is a workaround fix. Don't store uid issued by an external system in business template, it is not portable. Reindexing will fail. But I don't understand why those objects have to be stored in this business template.

DiffTool depends on deepdiff library to calculate diff but this only
works for pure string cases. In all other cases, we manually create
unified diff from old and new value. This led to problem between
how to display diff for large multiline content and for single line
content.

Related issue on Bug Module: https://nexedi.erp5.net/bug_module/20180810-13FBEFD

We have this [Do Not Test Required In Field View Form](https://www.erp5.com/documentation/developer/guideline/module/erp5-Guideline.Module.Creation#do-not-test-required-in-field-view-form rule) rule:
> This kind of constraint should be defined in Constraints documents and should to be checked in workflow transitions.
>
> Checking a field as "required" can cause problems like not saving the data when the user clicks on the save button. The same applies to the use of External Validators scripts in fields.

Currency view was not respecting this, there was both required fields and external validator. 
Also, the external validator was using an incorrect way of getting the "context document", so it was not working on RenderJS UI.

We are removing required fields and validator here, because this should be implemented using constraints instead.  To somehow preserve the same behavior, a new constraint is added in `erp5_base` and enabled in `erp5_configurator_standard`. Custom projects probably want to enable this constraint, but (as far as I know) we don't enable constraint by default. 

This  `Base_uniqueReferenceInFolderValidator` was apparently not used anywhere else and not working anymore, so we are just removing it.


/reviewed-on !710

This is needed to keep using the translation gadget.
See 9d0b0878

   Changes on ERP5Security: Define getFacebookUserEntry to reduce code duplication
   Add facebook support for login and logout (optional) on erp5_core, xhtml and credentials.

Any use of erp5_sql_transactionless_connection must end with an explicit SQL
commit, otherwise it does nothing and it may even leave SQL locks.

Contrary to InnoDB, TokuDB locks on such statement. test_InvoiceViewAsODT
is the only test that does not use erp5_sql_transactionless_connection
(other tests do via IdTool), breaking the next test
(test_PackingListEditAndInvoiceRule) with "Lock wait timeout exceeded" error.

One would except that the tests use the same instance of
erp5_sql_transactionless_connection, and in this case it would not fail, but
for bad reasons, tests alternate between 2 different ZODB Connection instances.

Here is the real fix :

-      output_dict["phone"] = organisation_phone.getDefaultTelephoneCoordinateText() or err("phone")
+      output_dict["phone"] = organisation_phone.getCoordinateText() or err("phone")

[erp5_web_renderjs_ui_test] Update test for Historical Revision Link so as not to display empty diffs

This change is based on the change in DiffTool: 610a15b3
where we don't display diffs for data types whose value is None, '' or empty data types.

When the listbox is in 'select' mode, lines are by default unselected.
Then, user can decide if he want to include/exclude selected lines.

Merge nearly identical listbox handlebars template.

Fix display of the selection checkbox on mobile.

Use label to render cell subgadget, so that clicking on the text modify the checkbox state.

Keep full text search at the end when including/excluding.

Use data- attribute to store the checkbox uid.

Change cursor for listbox line label.

User text query is always considered as an argument of an AND complex query.

Diff Tool: Redirect to the context in case there is selection of more or less than 2 objects in a module for diff

Also, update portal action regarding the module selection and add tests

[erp5_core] DiffTool: Raise error in case the selection for diff in a listbox has object not equal to 2

Change in tests based on change in DiffTool in commit: 610a15b3