nexmark query10 decision to make

the TODO task in the nexmark java [query 10](https://github.com/apache/beam/blob/master/sdks/java/testing/nexmark/src/main/java/org/apache/beam/sdk/nexmark/queries/Query10.java#L122) shows that the implementation details of query 10 has yet to be decided.
```

// TODO
// Fix after PR: right now this is a specific Google added use case
// Discuss
it on ML: shall we keep GCS or use HDFS or use a generic beam filesystem way.
throw new UnsupportedOperationException("Disabled
after removal of GcsIOChannelFactory");

```

After it is decided, both java and python nexmark's query 10 needs to be implemented.

Imported from Jira [BEAM-10879](https://issues.apache.org/jira/browse/BEAM-10879). Original Jira may contain additional context.
Reported by: leiyiz.