Implement warning message when opening .pdex or .pdez files

Created by: SableRaf

Currently, it is possible to open and run a .pdez or .pdex file downloaded from the web without any extra steps. It could be wise to add a warning when opening a bundled sketch/mode/tool/library to tell a user to only run third-party code if they trust the author (similar to VSCode's restricted mode).

Note: Unlike VSCode and its extensions, the PDE won't run arbitrary code just when you open a sketch so this is is not an apples to apples comparison, but since we made it easier to execute arbitrary code on a machine running the PDE, it might still be a good idea to add that extra layer of security.

Edit: this was initially mentioned here https://github.com/processing/processing4/issues/559

Commencez par retracer le flux d’ouverture et d’exécution des fichiers .pdex et .pdez fournis, y compris les sketches, les modes, les outils et les bibliothèques. C’est terminé lorsque les utilisateurs voient un avertissement de confiance avant d’exécuter du code tiers téléchargé, avec un comportement conforme au périmètre de sécurité prévu.