Improve Automated Tests maintenance

[DavidePrincipi]

The test pipeline runs on GitHub Actions and needs updates for its components. Now every NS8 component defines its own script and workflow. This is very flexible but requires heavy maintenance when Renovate opens many PRs to update RobotFramework-Browser dependency.

Proposed solution

Substitute the individual scripts with a call to a shared GitHub action, like we already do for the build process.

See also

• https://mattermost.nethesis.it/nethesis/pl/qkax8ci7xtyi5ne3yrtszq4joh