Check for service revision existence

[cortadocodes]

Contents (#680)

IMPORTANT: There is 1 breaking change.

Enhancements

• 💥 BREAKING CHANGE: Use cloud URIs by default for datasets in output manifests
• Add comments around checking for service revision existence
• Improve error when octue.services topic doesn't exist

Fixes

• Raise error if service revision subscription doesn't exist when no service registry is in use
• Remove octue.services prefix from subscription names

Refactoring

• Avoid repeated conversion to Pub/Sub ID for a service

---

Upgrade instructions

💥 Use cloud URIs by default for datasets in output manifests

Set use_signed_urls_for_output_datasets to True in the app configuration to keep using signed URLs for datasets in output manifests.