Merge '8-add-api-request-error-handling' into 'main'

Implements a proper handling of any errors on API requests by introducing a helper function that can be integrated in the RXJS HTTP client chains. The function logs the error to the console and shows a snackbar with a generic error message. Additionally, all components were updated to integrate a retry button that is only displayed when fetching the data fails. The retry button is implemented as a reusable component.

Closes #8 (closed)