Update workflow quickstarts to be services

## Describe the feature

Currently the workflow quickstarts are console applications which are very limited to be used with the workflow management operations once they are started. All workflows are using WaitForExternalEvent when the order cost is over 5000 USD but the apps themselves can't receive events (easily).

I recommend to update all workflow apps to be services and to add HTTP endpoints to demonstrate the workflow management methods via the Dapr Workflow Client or direct HTTP calls.

Start by inventorying the workflow quickstart console applications and their existing WaitForExternalEvent usage. Review the Dapr Workflow Client and direct HTTP-call approaches, then define service endpoints that demonstrate workflow management operations and verify that the applications can receive external events.

Written by the indexing model from the issue text.