**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}`

) -> None:
        """
        Creates a new ACL entry on the specified object.
        See: https://cloud.google.com/storage/docs/json_api/v1/objectAccessControls/insert
        :param bucket_name: Name of a bucket_name.
        :param object_name: Name of the object. For information about how to URL encode
            object names to be path safe, see:
            https://cloud.google.com/storage/docs/json_api/#encoding
        :param entity: The entity holding the permission, in one of the following forms:
            user-userId, user-email, group-groupId, group-email, domain-domain,
            project-team-projectId, allUsers, allAuthenticatedUsers
            See: https://cloud.google.com/storage/docs/access-control/lists#scopes
        :param role: The access permission for the entity.
            Acceptable values are: "OWNER", "READER".
        :param generation: Optional. If present, selects a specific revision of this object.
        :param user_project: (Optional) The project to be billed for this request.
            Required for Requester Pays buckets.
        """
        self.log.info("Creating a new ACL entry for object: %s in bucket: %s", object_name, bucket_name)
        client = self.get_conn()
        bucket = client.bucket(bucket_name=bucket_name)
        blob = bucket.blob(blob_name=object_name, generation=generation)
        
        blob.acl.reload()
        blob.acl.entity_from_dict(entity_dict={"entity": entity, "role": role})
        if user_project:
            blob.acl.user_project = user_project
        blob.acl.save()
        self.log.info("A new ACL entry created for object: %s in bucket: %s", object_name, bucket_name)
    def compose(self, bucket_name: str, source_objects: List[str], destination_object: str) -> None: