add qt5 package (#55)

Qt 5.15.18-lts-lgpl (QtBase + QtCharts) built from source as shared
libraries. Provides headers, shared libs, and tools (moc, rcc, uic)
for building cabana in openpilot without system Qt5 packages.

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

qt5/pyproject.toml

@@ -0,0 +1,15 @@
+[build-system]
+requires = ["setuptools>=64", "wheel"]
+build-backend = "setuptools.build_meta"
+
+[project]
+name = "qt5"
+version = "5.15.18"
+description = "Qt 5.15 (QtBase + QtCharts)"
+requires-python = ">=3.8"
+
+[tool.setuptools.packages.find]
+include = ["qt5*"]
+
+[tool.setuptools.package-data]
+qt5 = ["install/**/*"]