0.43.1: Improved CUDA setup/diagnostics + 8-bit serialization, CUDA 12.4 support, docs enhancements

Improvements:

• Improved the serialization format for 8-bit weights; this change is fully backwards compatible. (#1164, thanks to @younesbelkada for the contributions and @akx for the review).
• Added CUDA 12.4 support to the Linux x86-64 build workflow, expanding the library's compatibility with the latest CUDA versions. (#1171, kudos to @matthewdouglas for this addition).
• Docs enhancement: Improved the instructions for installing the library from source. (#1149, special thanks to @stevhliu for the enhancements).

Bug Fixes

• Fix 4bit quantization with blocksize = 4096, where an illegal memory access was encountered. (#1160, thanks @matthewdouglas for fixing and @YLGH for reporting)

Internal Improvements:

• Tests: improve memory usage (#1147, thanks @matthewdouglas)
• Add CUDA 12.4 to docs/install helper (#1136, thanks @matthewdouglas)
• Minor type/doc fixes (#1128, thanks @akx)
• Reformat Python code with Ruff (#1081, thanks @akx)
• Rework of CUDA/native-library setup and diagnostics (#1041, thanks @akx)