[AI] Add ONNX Runtime GPU acceleration install flow to AI preferences

[andriiryzhkov]

Adds a GPU ONNX Runtime installer to the AI preferences tab as an alternative to the shell/PowerShell scripts in tools/ai/, for users who'd rather not run them from a terminal. Open preferences → AI tab → click install → restart darktable. Both paths consume the same data/ort_gpu.json manifest and produce the same install layout – they need to stay in sync.

What it does

• Detects GPU (NVIDIA via nvidia-smi, AMD via rocminfo + multi-source ROCm version cascade, Intel via lspci + libze_loader).
• Downloads and SHA-256-verifies the matching archive, extracts via libarchive, probes the installed library to confirm it loads.
• On Windows, bundles cuDNN + CUDA-runtime DLLs from the system toolkit; pulls the OpenVINO runtime as a second download for Intel/Windows.
• On Linux, clears PT_GNU_STACK PF_X on installed .so files so glibc ≥ 2.41 will dlopen AMD's MIGraphX wheels (they ship with the flag set; newer glibc otherwise rejects them silently).
• Auto-redetects after install and writes plugins/ai/ort_library_path.

Parity with the scripts

The two paths are peers, not master/slave. Both must agree on package selection, install paths, checksum verification, archive layout (including preserve_layout for auditwheel-bundled wheels), and post-install validation. They both read data/ort_gpu.json; any change to detection rules, install destinations, or supported variants needs landing in both.