Add support for darwin_arm64

[jab]

Describe the bug

This codelab doesn't work on modern Macs; it fails with a toolchain error.

Here is what happens trying to complete Section 1: Hello, Bazel!:

nix_bazel_codelab on main
❯ bazel run //java/src/main/java/bazel/bootcamp:HelloBazelBootcamp  # 
ERROR: /private/var/tmp/_bazel_jab/3275b5a8772ff1ba5c3c27df62a9b077/external/local_config_cc/BUILD:48:19: in cc_toolchain_suite rule @local_config_cc//:toolchain: cc_toolchain_suite '@local_config_cc//:toolchain' does not contain a toolchain for cpu 'darwin_arm64'
...

Environment

• OS name + version: macOS 14.3.1 (latest, released 2024-02-08)
• Version of the code: latest (revision 9bfa6d2, dated 2024-02-12)