Add HNS folders samples

[bajajneha27]

Add following samples for HNS folders:

• Sample for creating bucket with HNS configuration, region tag : storage_create_bucket_hierarchical_namespace.
• Sample for create, get, update, list, rename and delete folder operations in storage-control with following region tags:
  • storage_control_create_folder
  • storage_control_delete_folder
  • storage_control_get_folder
  • storage_control_list_folders
  • storage_control_rename_folder

Please use PR#26020 and PR#26021 for reference.

[cojenco]

Completed via #1285 and GoogleCloudPlatform/python-docs-samples#11843