Replace webpacker with modern rails javascript tooling

[indiebrain]

webpacker has been retired. New Rails applications use https://github.com/rails/jsbundling-rails.

We should migrate this project to use the new standard rails tooling. https://github.com/rails/jsbundling-rails/blob/main/docs/switch_from_webpacker.md

[xjunior]

@indiebrain we're currently in the process of switching to vite in nitro. I'm not sure if we use jsbundling-rails in any active project. I'm not opposing to this change, just giving this a second thought.

[gbmoretti]

IMO for interview pourposes we should stick with Rails's defaults.