Write API documentation for all desired endpoints #29

Requirements

• Write an API documentation for all desired endpoints defined in the product backlog
• Make sure input and output are aligned with existing endpoints in the backend project.
• Optionally mark which endpoints are currently in use and which are planned
• You can use any form of styling or build system, but the docs should be able to be hosted as statics on s3.
• It's open to choose to host the API docs close to the endpoints or on their own.