[Packaging][Python] Add support for Python 3.15

[raulcd]

Describe the enhancement requested

Describe the enhancement requested

Similar to the Python 3.13 one:

• [Python][Packaging] Support Python 3.13 and upload wheels #43519

And 3.14:

• [Python][Packaging] Support Python 3.14 and upload wheels #47438

Python 3.15 is currently in a beta 2 status (https://discuss.python.org/t/python-3-15-0-beta-2-is-here/107610) and is expected to have a final release in October this year (https://devguide.python.org/versions).

We should ensure we are fully ready to support Python 3.15 for the PyArrow 26 release that will happen around the same time.

(equivalent PR for Python 3.14: #47616)
(equivalent PRs for Python 3.13: #43539, #44193, )
(issue that added free-threaded support for 3.13: #43536)
(equivalent PR for Python 3.12: #37901)

Component(s)

Python, Packaging

[raulcd]

I've been able to validate that on top of the following PR:

• GH-48028: [Python][Packaging] Update quay.io base manylinux and musllinux images for Python wheels and remove cp313t #50082

I can build a wheel for Python 3.15 on manylinux and run import and run all tests successfully with:

$ ARCHERY_DEBUG=1 ARCH=amd64 PYTHON=3.15 PYTHON_ABI_TAG=cp315 PYTHON_IMAGE_TAG=3.15 archery docker run -e SETUPTOOLS_SCM_PRETEND_VERSION=24.0.0.dev164 python-wheel-manylinux-2-28
...
INFO:auditwheel.wheeltools:New WHEEL info tags: cp315-cp315-manylinux_2_28_x86_64
INFO:auditwheel.main_repair:
Fixed-up wheel written to /arrow/python/repaired_wheels/pyarrow-24.0.0.dev164-cp315-cp315-manylinux_2_28_x86_64.whl
+ popd
/


$ ARCHERY_DEBUG=1 ARCH=amd64 PYTHON=3.15 PYTHON_ABI_TAG=cp315 PYTHON_IMAGE_TAG=3.15-rc archery docker run python-wheel-manylinux-test-unittests
...
SKIPPED [1] usr/local/lib/python3.15/site-packages/pyarrow/tests/test_util.py:215: Timezone database is already provided.
SKIPPED [3] usr/local/lib/python3.15/site-packages/pyarrow/tests/conftest.py:99: nonumpy NOT enabled
================================================================= 7550 passed, 666 skipped, 15 xfailed, 2 xpassed, 12 warnings in 134.58s (0:02:14) ==================================================================

The only thing that was blocking and I had to manually remove from our build process is libcst and the type stubs as there's now wheel built for libcst and I wasn't able to build one due to PyO3 check for unsupported cp315.