Add support for .tar.br to http_archive

Description of the feature request:

I've got a bunch of large, compressible archives for input dependencies to our build. These take a long time to decompress as part of the loading phase.

https://github.com/google/brotli trades off decompression speed for compression time in a way which is quite interesting. Archives are compressed once, and read by a bunch of clients. https://www.opencpu.org/posts/brotli-benchmarks/ has some benchmarks.

I'd love to be able to pull in dependencies as .tar.br files and get the improved decompression times.

Which category does this issue belong to?

External Dependency

What underlying problem are you trying to solve with this feature?

No response

Which operating system are you running Bazel on?

No response

What is the output of bazel info release?

No response

If bazel info release returns development version or (@non-git), tell us how you built Bazel.

No response

What's the output of git remote get-url origin; git rev-parse HEAD ?

No response

Have you found anything relevant by searching the web?

No response

Any other information, logs, or outputs that you want to share?

No response