Products-zcatalog

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- Moved `Products.ZCatalog.Lazy` module to `ZTUtils.Lazy`.

- Add configure.zcml with deprecatedManageAddDelete directives.

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- 12: Add request cache for index results to all UnIndex subclasses.

- Add dependency on `five.globalrequest`.

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- 6, 7, 11: Run ZODB cache garbage collection during queries.

- 13: Deal with threshold value of None in add/delColum.

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- Make index-listing compatible with Zope 4.

- 5: Ignore None values in UnIndex instead of raising a TypeError.

- Add a new getCounter method to indices.

- Update to ZODB 4.0 as direct dependency.

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- Raise a TypeError when trying to index or lookup `None` in an UnIndex.
This is a required change for BTrees 4.0+ compatibility, which prevents
objects without a clear ordering definition from being inserted in a tree.

- No longer try to insert a None value into a field index in tests.

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- Restore ability for indexes to use extra query params.
See PR 1.

- Change `CatalogPlan.valueindexes` to avoid using a `len()` call on the
result of each index `uniqueValues` method. This was loading entire BTrees
into memory and caused excessive database load on startup.

- Correct `withLengths` argument name on `PathIndex.uniqueValues` to use
plural form, adhering to the interface specification.

- Clarify the `IUniqueValueIndex.uniqueValues` method description and
explicitly mention generators/iterators as potential return values.
The PathIndex was one example returning a generator for some time.

- Adjust `actual_result_count` for sorted queries where the sort index doesn't
contain all the documents. Fixes LP 1237141.

- Restore safeguard for using the `iterate over sort index` case and avoid
it while using limiting at the same time. Fixes LP 1236790.