oidc-based binary cache?

[Mic92]

Looks like niks3 soon gets a OIDC support: Mic92/niks3#135
This would actually help with security over using the nix-community cachix cache,
because it would remove the long-living tokens from our github CI.
Also we could potentially make our binary cache bigger if needed and we want to throw more money on it.

[Mic92]

Here are some numbers comparing s3 storage costs: https://github.com/Mic92/niks3/wiki/S3-Provider-Comparison

You may wonder, why niks3 over attic. Well with attic it more work to make it high-available i.e. using some load-balancer and postgres cluster. Meanwhile s3 providers already solved the scaling issue. With many people potentially depending on this cache having a single server for the binary cache seems bit risky.