erp5_xhtml_style.breadcrumbs tries to access portal_properties, which
does not exist anymore (see commit
8721c675dae39611de884a9e6d6301978954c8c5, in which CMFDefault was
dropped).

The migration code here allows access to the ERP5 interface, which would
be completely broken otherwise.

Products.CMFCore.CookieCrumbler's redirect support was moved to
Products.CMFDefault in CMF 2.3, cf:
- CMFCore: 387bd379fd9655aa1462715a04b4664f5c54974a
- CMFDefault: d319a68e8299e42a76f605ad79383bb78db14031

The absence of this backport when using CMF 2.3 creates regressions:
some redirects become Unauthorized.

'precondition' was an attribute from Products.CMFDefault. As we dropped
the latter, and the attribute has never been used in ERP5, we can delete
it.

cf commit 550e81b0bf68340e8f7c39902978024a17112943

Also some code refactoring.

ICookieCrumbler.credentialsChanged signature changed in Products.CMFCore
2.3.0-beta. We also update the patch on the same occasion.

... so that queryUtility can later access the correct ones.

Note: we do not necessarily want to register all tools.

It is no longer supported in CMF 2.3, see Products.CMFCore
754894460271f8562d03e8c51e6efcee7223a3ba.

It is no longer supported in CMF 2.3, see Products.CMFCore
be875bb45272ad6ad3c2e14d72a41295dc7389cf.

getToolByName(portal, 'portal_skins').REQUEST: AttributeError

testBusinessTemplate: When one Unit Test failed, subsequent tests were failing too as objects remained.

ZODB Components: BusinessTemplate: Products.ERP5Type.Base will never be migrated (InitGhostBase) so ignore it when migrating source files from FS.

All other Component modules must be kept alive during the REQUEST life (f523edc4).
However, Unit Tests modules should be kept alive until it finished executing and
this may span accross multiple REQUESTS.

Issue found out when migrating testBusinessTemplate to erp5_core_test which was
failing as the module was GC'ed and its top-level variables were reset to None by
the interpreter.

Not migrated:
  + testERP5Site: Checks Site creation and overrides setUp().
  + testERP5TypeInterfaces: Verifies that classes implements the Interfaces they claim to implement.
    => Should probably be integrated into coding style Unit Tests and done
       dynamically (MRO). Also, testERP5Interfaces imports code from that
       Unit Test and requires non-core bt5 to be installed.
  + testInvalidationBug: To-do (failing).
  + testPredicate: testDomainTool, inheriting from TestPredicateMixin, should be rewritten to not
    depend on erp5_apparel so that it can be moved to erp5_core_test.

Also, move manuallyInstallBusinessTemplate() and uninstallBusinessTemplate() from
ERP5TypeCommandLineTestCase to ERP5TypeTestCaseMixin as they are also used by
Live Unit Tests.

ERP5Type: {CSS,JS}Packer have never been used so delete them rather than migrating them to portal_components.

This reverts commit 1862fdf5.
Because of current ERP5Type.Core.Folder inheritance order, this commit
is not ready for inclusion in master just yet.

All ERP5UI-visible (hence needing to call allowedContentTypes) BTReeFolder2
instances should already inherit ERP5Type.Core.Folder, removing the need
for this monkey-patch.

In preparation of reordering Folder inheritance order.