Upgrade rules_cc 0.0.16 and rules_java 8.3.1

Both versions are again compatible with WORKSPACE mode on Bazel 8. The version also extends the compatibility down to Bazel 6.

Add repo_name = "com_google_protobuf" to examples/MODULE.bazel. Bazel 6,7,and 8 (in WORKSPACE mode) still expect this is the name of the repo. (Default value of --proto_compiler flag). There's no way to change this without breaking compatibility with WORKSPACE mode.

Remove local_repository(name = protobuf) from WORKSPACE. The repository is now consistently called com_google_protobuf in both WORKSPACE and Bzlmod mode.

Rename uses of @protobuf to @com_google_protobuf.

PiperOrigin-RevId: 695579489