Fix dependency on platforms

[allsey87]

From #1262 (comment)

Its probably the non-bzlmod code path - we don't explicitly depend on platforms at the moment which I guess is a bug; you probably need to add platforms to the workspace macro in rules_foreign_cc/repositories.bzl too?

The goal of this PR is properly integrate platforms into rules_foreign_cc. Merging this will hopefully unblock #1262. I am setting this as a draft for now since I am a bit short on time to work on it and just want to see how CI behaves when I declare the repository.

[allsey87]

Currently breaks CI with:

(15:29:29) ERROR: /workdir/test/BUILD.bazel:15:30: While resolving toolchains for target //test:shell_script_inner_fun (9a56767): No matching toolchains found for types //foreign_cc/private/framework:shell_toolchain.
To debug, rerun with --toolchain_resolution_debug='//foreign_cc/private/framework:shell_toolchain'

[allsey87]

Any ideas/hints on how to solve this one, @jsharpe?