basic authentication system using jsonwebtokens

Create a basic registration and login functionality for the platform.

For registration purpose, take the following as inputs from the user:

- username
- email
- password

Similarly, for login functionality, take the following input:

- email or username
- password

After registration/login, the api should give an output object consisting the user information and token.

No files, tests, or entry points are identified in the issue, so first locate the platform's API and user-management entry points. Define the registration and login flows around the listed inputs, and consider the work complete when both flows return user information and a token as specified.

Written by the indexing model from the issue text.