feat: add Pearson engine client

[andrey-canon]

Description

This adds a new client that allows to connect with the rti service provided by this pr

https://edunext.atlassian.net/browse/FUTUREX-830

Testing instructions

1. Add the following settings

PEARSON_ENGINE_API_CLIENT_ID = "blablba"
PEARSON_ENGINE_API_CLIENT_SECRET = "fsdfsdf"
PEARSON_ENGINE_API_URL = "http://example.com"

2. Run into a shell

from eox_nelp.api_clients.pearson_engine import PearsonEngineApiClient
from django.contrib.auth import get_user_model

api_client = PearsonEngineApiClient()
User = get_user_model()
user = User.objects.get(id=<your id>)

api_client.import_candidate_demographics(user)
api_client.import_exam_authorization(user, "course_id")

Before

After

Additional information

Include anything else that will help reviewers and consumers understand the change.

• Does this change depend on other changes elsewhere?
• Any special concerns or limitations? For example: deprecations, migrations, security, or accessibility.
• Link to other information about the change, such as Jira issues, GitHub issues, or Discourse discussions.

Checklist for Merge

• Tested in a remote environment
• Updated documentation
• Rebased master/main
• Squashed commits

[johanseto]

I don't like that the inner key has the same name of dict. But it is only an opinion. I leave it to your consideration