Investigate building for aarch64 Linux too

[fwcd]

This would be nice for use on a Raspberry Pi, especially given that from-source builds under QEMU take very long. We'd have to figure out whether building all the dependencies from scratch via vcpkg is the right approach or whether using the distribution-provided libraries would be better after all.

[fwcd]

ARM Linux runners are coming soon for open source, at which point we could revisit this: https://github.blog/changelog/2024-06-03-actions-arm-based-linux-and-windows-runners-are-now-in-public-beta/