Release a tarball artifact

[gridbugs]

This changes the github action to upload a tarball named like dune-2024-09-25-aarch64-apple-darwin.tar.gz. Extracting the tarball produces a directory named like dune-2024-09-25-aarch64-apple-darwin which contains the dune binary and the attestation file. This has several benefits over the current approach where users are required to download a dune exe directly:

• the executable bit remains set on the dune executable inside the tarball, so users don't need to chmod the binary
• the name of the downloaded file contains more information and is unique for each day so your downloads directory doesn't end up filled with files named "dune", "dune(1)", "dune(2)", etc.
• we have the flexibility to add more files to the archive in the future, such as including a readme file

Currently this just updates the github action - not the website - so this can't be merged as is. I'm opening this for review in its current state to get early feedback and to see if the deploy step of the github action works as expected (I couldn't figure out how to test this on my fork).

[gridbugs]

I started a manual run of the workflow here to test the deploy step: https://github.com/tarides/dune-binary-distribution/actions/runs/11035537631

[gridbugs]

As a conservative measure (until we fixed it), what do you think about publish bot the binary and the tar? We could remove the binary later?

Yep happy with this

[leostera]

@gridbugs is this mergeable?

[gridbugs]

I spoke with @maiste and they're going to integrate this into some other work they're doing.

[maiste]

The build failed. @gridbugs after discussing, the work in question will happen later. As we discussed, I will do some minors changes to fix it in the afternoon.

[maiste]

Closing in favor of #48.