Unit testing React components

[alcpereira]

Description

For unit testing the components, there is an handy library: Testing Library. This should be integrated with Vitest (look for articles that explains this stack Vitest + Testing Library).

Bonus: Investigate for Remix components (see here)

ACs

• Integrate Testing Library
• Write tests for the existing components (depending on how many components already exists, feel free to split the work and open new Issues)
• Update docs (docs/testing.md only the Components part)
• Add specific npm script to run this test, like test:react and a watch mode (if needed).

[alcpereira]

Current work in progress in #36