Add an simple HTTP testing workflow

[I-Dont-Remember]

What was changed?

Small changes to a couple scripts, added a new endpoint that reflects the request body so we can easily have an integration test workflows for HTTP requests & Extracting JSON variables without depending on external servers.

Why is this good for our users?

This is good because... improving testing.

Attestation

Below you'll find a checklist. For each item on the list, check one option and delete the other.

• Unit Tests
  • [x] This PR does not require tests.
• Documentation
  • [x] Docs have been updated.
• Integration Testing
  • [-] At minimum, ran the ./test_workflows/workflow_buddy_end_to_end_test_read_only.slackworkflow workflow and it was both successfully completed & outputs looked correct (We don't have a way to assert that changes are correct yet).