Introduce basic pyproject.toml, supporting existing build methods only (#2687)

* Add pyproject.toml with only name and dynamic fields

* Add build-system section to pyproject.toml with build requirements

Explicitly set the fallback build backend `setuptools.build_meta:__legacy__`

* Replace wheel.bdist_wheel import with setuptools equivalent

There is a deprecation warning that will be enforced in october 2025

* Package `requests[security]` is a no-op since 2.26.0, published 2021-07-13, use only `requests >= 2.26.0`

* Add setuptools package configuration to pyproject.toml

* Exclude packages found at top level with setuptools config

Exclude buildtools/backports package found at top level with setuptools config

* Add dynamic metadata in setup-wxsvg.py too to avoid failing the build

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Co-authored-by: Edouard Choinière <echoix@users.noreply.github.com>

pyproject.toml

@@ -0,0 +1,29 @@
+[project]
+name = "wxPython"
+dynamic = [
+    "authors",
+    "classifiers",
+    "dependencies",
+    "description",
+    "keywords",
+    "license",
+    "readme",
+    "scripts",
+    "urls",
+    "version",
+]
+
+[build-system]
+requires = [
+    "setuptools>=70.1",
+    "cython == 3.0.10",
+    "requests >= 2.26.0",
+    "sip == 6.9.1",
+]
+# Using "setuptools.build_meta:__legacy__" instead of "setuptools.build_meta" for now.
+# Allows to have access to the folder on the search path when building, like before.
+build-backend = "setuptools.build_meta:__legacy__"
+
+[tool.setuptools.packages.find]
+exclude = ["src", "buildtools*", "etgtools", "sphinxtools", "src", "unittests"]
+namespaces = false