**Description**

Support passing multiple prefixes to `GoogleCloudStorageListOperator` and `GoogleCloudStorageDeleteOperator` operators.

**Use case / motivation**

I have this folder structure in GCS bucket.

```
+-- year={year}
|   +-- month={month}
|       +--day={day}
|           +-- topic={topic1}
|                 +--file 1
|                 +--file 2
|                 +--file 3
|           +-- topic={topic2}
|                 +--file 1
|                 +--file 2
|                 +--file 3
|           +-- topic={topic3}
|                 +--file 1
|                 +--file 2
|                 +--file 3
|           +-- topic={topic4}
|                 +--file 1
|                 +--file 2
|                 +--file 3
|           +-- topic={topic5}
|                 +--file 1
|                 +--file 2
|                 +--file 3
|           +-- topic={topic6}
|                 +--file 1
|                 +--file 2
|                 +--file 3
|           +-- topic={topic7}
|       +--day={day}
|           +-- topic={topic1}
|                 +--file 1
|                 +--file 2
|                 +--file 3
|           +-- topic={topic2}
|                 +--file 1
|                 +--file 2
|                 +--file 3
|           +-- topic={topic3}
|                 +--file 1
|                 +--file 2
|                 +--file 3
|           +-- topic={topic4}
|                 +--file 1
|                 +--file 2
|                 +--file 3
|           +-- topic={topic5}
|                 +--file 1
|                 +--file 2
|                 +--file 3
|           +-- topic={topic6}
|                 +--file 1
|                 +--file 2
|                 +--file 3
|           +-- topic={topic7}
|                 +--file 1
|                 +--file 2
|                 +--file 3
|           ....
```

What I need to achieve is delete one day of objects. For example, I need to delete objects in `year=2020/month=08/day=19`. I can do that easily using `gsutils`. In `gsutil` you can delete them via wild card `gsutil ear=2020/month=08/day=19/*` but using the REST APIs you can't even if you use a prefix. The reason is there is no one prefix to get all the objects inside a folder. I achieved that by using multiple prefixes and for each prefix, I will get the list of objects. Unfortunately, I can't pass more than one prefix to the operators.

**Prefixes used**
- `year=2020/month=08/day=19/topic={topic1}`
- `year=2020/month=08/day=19/topic={topic2}`
- `year=2020/month=08/day=19/topic={topic3}`
- `year=2020/month=08/day=19/topic={topic4}`
- `year=2020/month=08/day=19/topic={topic5}`
- `year=2020/month=08/day=19/topic={topic6}`
- `year=2020/month=08/day=19/topic={topic7}`

for line in iter(process.stdout.readline, b""):
                        self.log.info(line.decode(self.output_encoding).rstrip())
                process.wait()
                if process.returncode:
                    raise AirflowException(f"Transform script failed: {process.returncode}")
            self.log.info("Transformation succeeded. Output temporarily located at %s", temp_output_dir_path)
            files_uploaded = []
            
            for upload_file in temp_output_dir_path.glob("**/*"):
                if upload_file.is_dir():
                    continue
                upload_file_name = str(upload_file.relative_to(temp_output_dir_path))
                if self.destination_prefix is not None:
                    upload_file_name = f"{destination_prefix_interp}/{upload_file_name}"
                self.log.info("Uploading file %s to %s", upload_file, upload_file_name)
                try:
                    destination_hook.upload(
                        bucket_name=self.destination_bucket,
                        object_name=upload_file_name,
                        filename=str(upload_file),
                        chunk_size=self.chunk_size,
                        num_max_attempts=self.upload_num_attempts,
                    )
                    files_uploaded.append(str(upload_file_name))
                except GoogleCloudError:
                    if self.upload_continue_on_fail:
                        continue
                    raise
            return files_uploaded
class GCSDeleteBucketOperator(GoogleCloudBaseOperator):