use rapids-build-backend

[jameslamb]

Description

Contributes to https://github.com/rapidsai/build-planning/issues/31 Contributes to https://github.com/rapidsai/dependency-file-generator/issues/89

Proposes introducing rapids-build-backend as this project's build backend, to reduce the complexity of various CI/build scripts.

Checklist

• [x] I am familiar with the Contributing Guidelines.
• [x] New or existing tests cover these changes.
• [x] The documentation is up to date with these changes.

[jameslamb]

It looks like the conda-python-tests jobs are failing here, like this:

FAILED tests/basicpreds/test_intersections.py::test_one_pair - AssertionError: Series Expected type <class 'pandas.core.series.Series'>, found <class 'pandas.core.indexes.base.Index'> instead
FAILED tests/basicpreds/test_intersections.py::test_two_pairs - AssertionError: Series Expected type <class 'pandas.core.series.Series'>, found <class 'pandas.core.indexes.base.Index'> instead
FAILED tests/basicpreds/test_intersections.py::test_one_pair_with_overlap - AssertionError: Series Expected type <class 'pandas.core.series.Series'>, found <class 'pandas.core.indexes.base.Index'> instead
FAILED tests/basicpreds/test_intersections.py::test_two_pairs_with_intersect_and_overlap - AssertionError: Series Expected type <class 'pandas.core.series.Series'>, found <class 'pandas.core.indexes.base.Index'> instead
FAILED tests/basicpreds/test_intersections.py::test_one_pair_multilinestring - AssertionError: Series Expected type <class 'pandas.core.series.Series'>, found <class 'pandas.core.indexes.base.Index'> instead
FAILED tests/basicpreds/test_intersections.py::test_three_pairs_identical_has_ring - AssertionError: Series Expected type <class 'pandas.core.series.Series'>, found <class 'pandas.core.indexes.base.Index'> instead
FAILED tests/basicpreds/test_intersections.py::test_three_pairs_identical_no_ring - AssertionError: Series Expected type <class 'pandas.core.series.Series'>, found <class 'pandas.core.indexes.base.Index'> instead

(build link)

I see the same failures on #1384 (build link), so fairly confident that they're not related to the changes here.

[jameslamb]

/merge