docs: add Hierarchical Namespace Bucket and Folders samples

[BenWhitehead]

New samples

• storage_create_bucket_hierarchical_namespace
• storage_control_create_folder
• storage_control_delete_folder
• storage_control_get_folder
• storage_control_list_folders
• storage_control_rename_folder

Fixes #2569

[snippet-bot]

Here is the summary of changes.

You are about to add 6 region tags.

• samples/snippets/src/main/java/com/example/storage/control/v2/CreateFolder.java:19, tag storage_control_create_folder
• samples/snippets/src/main/java/com/example/storage/control/v2/CreateHierarchicalNamespaceBucket.java:19, tag storage_create_bucket_hierarchical_namespace
• samples/snippets/src/main/java/com/example/storage/control/v2/DeleteFolder.java:19, tag storage_control_delete_folder
• samples/snippets/src/main/java/com/example/storage/control/v2/GetFolder.java:19, tag storage_control_get_folder
• samples/snippets/src/main/java/com/example/storage/control/v2/ListFolders.java:19, tag storage_control_list_folders
• samples/snippets/src/main/java/com/example/storage/control/v2/RenameFolder.java:19, tag storage_control_rename_folder

---

This comment is generated by snippet-bot.
If you find problems with this result, please file an issue at:
https://github.com/googleapis/repo-automation-bots/issues.
To update this comment, add snippet-bot:force-run label or use the checkbox below:

• Refresh this comment