samples(storage): add Managed Folders Samples

[sydney-munro]

Description

Fixes https://github.com/googleapis/google-cloud-go/issues/10343

Note: Before submitting a pull request, please open an issue for discussion if you are not associated with Google.

Checklist

• [x] I have followed Contributing Guidelines from CONTRIBUTING.MD
• [x] Tests pass: go test -v ./.. (see Testing)
• [x] Code formatted: gofmt (see Formatting)
• [x] Vetting pass: go vet (see Formatting)
• [ ] These samples need a new API enabled in testing projects to pass (let us know which ones)
• [ ] These samples need a new/updated env vars in testing projects set to pass (let us know which ones)
• [ ] This sample adds a new sample directory, and I updated the CODEOWNERS file with the codeowners for this sample
• [ ] This sample adds a new Product API, and I updated the Blunderbuss issue/PR auto-assigner with the codeowners for this sample
• [ ] Please merge this PR for me once it is approved

[snippet-bot[bot]]

Here is the summary of changes.

You are about to add 4 region tags.

- [storage/control/create_managed_folder.go:17](https://github.com/GoogleCloudPlatform/golang-samples/blob/c7ffaf6a0d5e5298ae0c86739acdf07663f4fad0/storage/control/create_managed_folder.go#L17), tag `storage_control_managed_folder_create` - [storage/control/delete_managed_folder.go:17](https://github.com/GoogleCloudPlatform/golang-samples/blob/c7ffaf6a0d5e5298ae0c86739acdf07663f4fad0/storage/control/delete_managed_folder.go#L17), tag `storage_control_managed_folder_delete` - [storage/control/get_managed_folder.go:17](https://github.com/GoogleCloudPlatform/golang-samples/blob/c7ffaf6a0d5e5298ae0c86739acdf07663f4fad0/storage/control/get_managed_folder.go#L17), tag `storage_control_managed_folder_get` - [storage/control/list_managed_folder.go:17](https://github.com/GoogleCloudPlatform/golang-samples/blob/c7ffaf6a0d5e5298ae0c86739acdf07663f4fad0/storage/control/list_managed_folder.go#L17), tag `storage_control_managed_folder_list`

---

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