feat: add rule for downloading private github assets

[jungleraptor]

Github release assets from private repositories are not available at the download link url like public assets.

They require a relatively complicated sequence of http requests to get the actual content - which is not possible with any of the OTB bazel donwloader rules (http_file, http_archive, etc..).

Luckily someone else has already solved this problem for us:
https://www.stevenengelhardt.com/2023/05/23/practical-bazel-downloading-private-release-assets-from-github/

I've taken this code so that we can download private github assets

Related: https://github.com/swift-nav/starling/pull/9180

[pcrumley]

Is the best way to take in upstream functions like this copying and pasting them?

Kind of feels like a step backwards when it comes to dependency management but I assume this is just commonplace in bazel

[jungleraptor]

Is the best way to take in upstream functions like this copying and pasting them?

Kind of feels like a step backwards when it comes to dependency management but I assume this is just commonplace in bazel

It's just some guys blog post - there's a chance that this made it into one of the more popular upstream utility rules sets (like bazel-lib, or skylib) but admittedly I did not check.

But yes in general there's a lot of copy pasting rules in the bazel ecosystem. The new modules system and the Bazel Central Registry aims to improve this situation but it's still pretty early.