2023-09-01 ECA Sprint: ECA and http services

[ECA am http services](https://ecaguide.org/library/simple/eca_and_http_services/) This model has 2 parts: 1. It demonstrates how to use API endpoints provided by the [http_client_manager](https://www.drupal.org/project/http_client_manager) module and access the data they receive from remote services. 2. It then also demonstrates how to use ECA endpoints to control the access to that endpoint and build up a response to it. In a follow-up model, we will then show how the ECA endpoint can be made available to the HTTP Client Manager, so that one Drupal site could be offering an API endpoint controlled by ECA, and another Drupal site then requested data from that API.