Consistent bazel rule names open source gapic packages

Currently three different versions are used in the [template](https://github.com/googleapis/rules_gapic/blob/main/bazel/src/main/java/com/google/api/codegen/bazel/BUILD.bazel.gapic_api.mustache).

```
name = "google-cloud-{{assembly_name}}-{{version}}-java",
name = "gapi-cloud-{{assembly_name}}-{{version}}-go",
name = "{{assembly_name}}-{{version}}-py",
```

It simplifies downstream tooling if these follow a consistent pattern. What are the consequences of changing these to a single format?