Implements Orange Cameroon Mobile Money service

[ajeety4]

Product Description

Implements Orange Cameroon Mobile Money service.

• Introduced a provider field on the MoMo config model to enable support for multiple payment providers.
• Added the payment request API service integration for Orange Cameroon.
• Added the payment status API service integration for Orange Cameroon.
• Performed few minor fixes.

Technical Summary

Ticket

Feature Flag

MTN_MOBILE_WORKER_VERIFICATION

Safety Assurance

Safety story

Tested on local.

Automated test coverage

Updated. API calls are mocked.

QA Plan

QA ticket to be created.

Migrations

• The migrations in this code can be safely applied first independently of the code. Pay particular attention to backward incompatible operations like RemoveField, RenameField, RemoveConstraint, and others described here that can cause errors when migrations are applied to a live database.

Rollback instructions

• This PR can be reverted after deploy with no further considerations

Labels & Review

• Risk label is set correctly
• The set of people pinged as reviewers is appropriate for the level of risk of the change

[kaapstorm]

Non-blocking suggestion: It would be cool, either somewhere in the code or in the tests, to have an example of what request responses look like.