erp5_core: move back ContributionPredicate to file system
This partially reverts 96bbfad2 (ZODB Components: More Documents to migrate from Products.ERP5.Document., 2020-06-29) because of test failures:
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ERROR: test_GET_on_document (testWebDavSupport.TestWebDavSupport)
Get data from document in webdav
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Traceback (most recent call last):
File "Products/ERP5/tests/testWebDavSupport.py", line 214, in test_GET_on_document
document = document_module[filename]
File "OFS/ObjectManager.py", line 783, in __getitem__
raise KeyError, key
KeyError: 'P-DMS-Presentation.3.Pages-001-en.odp'