Port to Bazel Modules

[finn-ball]

Port the project to bazel modules as defined here:
https://bazel.build/external/module

As of Bazel 7, this is now the default way to bring in dependencies:
https://blog.bazel.build/2023/12/11/bazel-7-release.html

[finn-ball]

I have a rough draft working with your project, I can aim to create a PR in the next couple of days if this interests you.

[mvukov]

Hi, thanks for the initiative. Sure, please open a PR and we can iterate there.

[finn-ball]

This port is made a lot easier if we manage to port rules_boost:
nelhage/rules_boost#546

Got this merged :)

[mvukov]

Done in #14 .