Wrong GHDL package downloaded on macOS ARM (Intel build used)

[swittlich]

On macOS running on Apple Silicon (ARM), the extension currently downloads the Intel (x86_64) GHDL build instead of the ARM version. This results in GHDL not working correctly unless Rosetta is installed. The platform detection does not seem to properly differentiate between x86_64 and arm64 on macOS.

[hendrikmennen]

X64 is always used when Arm64 is not provided. Currently it is not defined. We can simply add the newest packages which support Arm