[chore] jwt authentication implementation

[mumer92]

Description

LEARNER-8796

For in-app purchases, we need to make api calls to e-commerce backend of edx-platform. E-commerce apis use jwt authentication instead of bearer authentication, so we need to migrate from bearer to jwt and also let users use the application who have already logged in. New refresh token calls for existing apis fetch the new jwt token using the old refresh_token, once updated, application will be migrated to fetch jwt token, while if a user signs in again, application will receive jwt token.

Implementation of following authentication cases:

• [ ] Username/Password
• [ ] Social login
• [ ] Token Expiration
• [ ] Webview Authentication

How to test this PR

• [ ] Mobile client can authenticate and use ecommerce endpoints
• [ ] Mobile client can still authenticate and use webviews and other endpoints

Notes:

Currently jwt implementation is available on iap sandbox

[saeedbashir]

@mumer92 I haven't see any change to request JWT token in case of social auth.

[saeedbashir]

@asifbilal786 You can review this PR.

[saeedbashir]

@mumer92 tests are failing