Repository and domain for planets

## Description
After seeing the response times of the planets, it will take some time for the API to response with the data and for it to be processed in time for the planets being rendered. Additionally if modifications were needed for the planets, the current implementation would have no way of interacting with the planets as their data would have to be actively saved.

## Acceptance Criteria

- The repository exists and can be accessed
- Domain objects can be passed in and are accessed
- Only the usecase can interact with the repository
- The rendered objects are the view and should not be touching the domain

## Implementation

- Create a Repository for planets
- Store the data in an array
- Implement the repository in the use case
- Pass the domain into the repository
- Do that you can extract the data from the repository using the planetCode (from the view model)