Create environment variables to switch between DEV and PROD servers

[amellie]

User Story

As a developer
I would like to run my app locally or in production easily
So that I do not need to modify hardcoded URLs (or any other settings) before running the app

Requirements

• URLs, including database and end point URLs should not be hardcoded. They should be stored in the environment variables
• Ensure that passwords are not hardcoded
• The path to the upload folder should also be put as part of the environment variable, so that the client can change the folder name/location of the folder if necessary

See https://trekinbami.medium.com/using-environment-variables-in-react-6b0a99d83cf5