This allows using expressions that have an output_field that is a
BooleanField to be used directly in a queryset filters, or in the
When() clauses of a Case() expression.
Thanks Josh Smeaton, Tim Graham, Simon Charette, Mariusz Felisiak, and
Adam Johnson for reviews.
Co-Authored-By: NyanKiyoshi <hello@vanille.bid>
The query used a construct of qs.annotate().values().aggregate() where
the first annotate used an F-object reference and the values() and
aggregate() calls referenced that F-object.
Also made sure the inner query's select clause is as simple as possible,
and made sure .values().distinct().aggreate() works correctly.
A field for storing periods of time - modeled in Python by timedelta. It
is stored in the native interval data type on PostgreSQL and as a bigint
of microseconds on other backends.
Also includes significant changes to the internals of time related maths
in expressions, including the removal of DateModifierNode.
Thanks to Tim and Josh in particular for reviews.
