Add backend message loading to Home component and update environment …

[SamuelCarmona83]

This pull request includes changes to improve the front-end functionality and configuration of the project. The most important changes include updating environment variables, enhancing the Home component to fetch data from the backend, and updating the store reducer to handle new actions.

Environment Variables Update:

• .env.example: Updated environment variable names to use the VITE_ prefix for front-end compatibility.

Front-End Enhancements:

• src/front/pages/Home.jsx: Enhanced the Home component to fetch a message from the backend and display it, including error handling and conditional rendering based on the store state.

Store Updates:

• src/front/store.js: Added a new action type set_hello in the store reducer to handle the fetched message from the backend.