Add basic testing configuration

[alejorrojas]

Hi! I love the template and find it extremely useful. However, I haven't seen any testing framework/library support integrated. I would like to know if there is any specific reason behind this decision, or if it would be a great idea to make a PR to integrate basic configuration files for testing with Jest, React Testing Library, and Cypress.

I consider these are frequently used tools, and the improvement could save some time.

Let me know!