This introduces several new functions in

reviewboard.reviews.testing.queries.review_requests for building

expected queries for unit tests:

get_review_requests_accessible_q()
get_review_requests_from_user_q()
get_review_requests_to_group_q()
get_review_requests_to_user_q()
get_review_requests_to_user_directly_q()
get_review_requests_to_user_groups_q()
get_review_requests_to_or_from_user_q()
get_review_requests_accessible_prep_equeries()
get_review_requests_accessible_equeries()
get_review_requests_accessible_from_user_equeries()
get_review_requests_accessible_to_group_equeries()
get_review_requests_accessible_to_user_equeries()
get_review_requests_accessible_to_user_directly_equeries()
get_review_requests_accessible_to_user_groups_equeries()
get_review_requests_accessible_to_or_from_user_equeries()

This covers all the queries used via ReviewRequestManager, offering

both Q-expressions (for embedding in other queries, needed for the

datagrids) and standalone queries.
The logic for building Q-expressions is verbose, checking each

combination of states individually and returning complete Q-expressions

as often as possible. Truth tables and comments help document these.

This is built this way in order to ensure we're testing against

fully-known expressions, making it harder to introduce a bug in any

queries.
Unit tests for ReviewRequestManager have been updated to use these.

There's still work that should be done to make these tests more

comprehensive, but between them, upcoming dashboard unit test changes,

and API tests, we have complete coverage.
As an implementation note, this is also the first change to make use of

the new PEP 692 support for defining **kwargs arguments using

TypedDict, helping with the complexity of the number of arguments

these functions all take. With this PEP, a value in the TypedDict

cannot also be present as a standalone argument (to, say, type-narrow

or override a value), and cannot be passed to a function if also

present in kwargs, so we have to resort to manipulating kwargs

directly. This is a reasonable trade-off in this code, but we'll need

to consider this approach elsewhere on a case-by-case basis.

All unit tests pass.