feat(storage): add turbo replication (RPO) samples

[BrennaEpp]

Fixes #2252

Requires googleapis/google-cloud-go#5003

Added some functionality to wait for a bucket to be propagated for tests

[snippet-bot]

Here is the summary of changes.

You are about to add 4 region tags.

• storage/buckets/create_bucket_turbo_replication.go:17, tag storage_create_bucket_turbo_replication
• storage/buckets/get_rpo.go:17, tag storage_get_rpo
• storage/buckets/set_rpo_async_turbo.go:17, tag storage_set_rpo_async_turbo
• storage/buckets/set_rpo_default.go:17, tag storage_set_rpo_default

---

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

[ddelgrosso1]

Overall LGTM but I defer to the Go experts.

[tritone]

Few minor things, sorry I didn't review this earlier! Feel free to merge once fixed.