explore building an arm64 variant

[clux]

As energy use and costs for arm64 compute is lower than ever (e.g. aws graviton), it makes sense to provide an arm64 tagged build if possible/necessary.

Do not have a lot of experience in this avenue yet so input welcome. But will try to look into this shortly. Only thing I've found so far is the rust on graviton doc.

Optimising for energy use is probably the main thing we as software engineers can do inside our occupation towards climate change (outside; direct action :fist_raised: :heart_on_fire:).