Linux arm64 support

[corbindavenport]

The Dart SDK can run on arm64 Linux, so it could be possible for Nexus Tools to add support for arm64 Linux and Chrome OS. There are some factors to consider.

1. Dart SDK doesn't support cross-compile, so this would need to wait until GitHub Actions offers arm64 Linux runners, which is expected by the end of 2024.
2. Google doesn't currently offer Platform Tools packages for arm64 Linux. It would need to use a different recompiled version, or maybe the official x86_64 version could run under box64. If it's the latter option, Nexus Tools would need to check if box64 is installed, and if not, help the user set it up.
3. Nexus Tools usage on Linux and Chrome OS trails far behind Windows and macOS, likely because most people just install Platform Tools through the included software repositories. There might not be any significant demand for arm64 support if the demand for x86_64 is already so low.

The Dart SDK also supports Linux arm32, but that's increasingly dying as a desktop platform, and it's unclear if Platform Tools would work on that.