Create product rest endpoints

[louwie17]

We should persist the product data on the server by using a REST api.
Endpoints that we would want:

• get all products (GET)
• create new product (POST)

Example of a rest endpoint call: http://localhost:8888/index.php?rest_route=/store/v1/products
For now we can use get_option and update_option to persist the data.

Here is some documentation for creating a new REST route: https://developer.wordpress.org/rest-api/extending-the-rest-api/adding-custom-endpoints

We should follow the controller pattern as described here:
https://developer.wordpress.org/rest-api/extending-the-rest-api/adding-custom-endpoints/#the-controller-pattern

These endpoints can be public. Something like Postman would be helpful to test the API endpoints.