HTTP Endpoint activity Swashbuckle integration

When implementing APIs as workflows, one should be able to describe its operations and integrate with Swashbuckle.

As part of this work, let's take into account the following topics and issues:

- [ ] #2971
- [x] #3498
- [ ] #2912
- [ ] #2700

Elsa 2 already supports Swashbuckle integration, so we can probably port over a large portion of it.

Start by reviewing the related issues #2971, #3498, #2912, and #2700 to understand the required HTTP endpoint work. Then compare Elsa 2's existing Swashbuckle integration. Done means workflow API operations can be described and integrated with Swashbuckle.

Written by the indexing model from the issue text.