Make the addon-template use vite

[BlueCutOfficial]

Apps used in test scenarios are built out of an app template. Recently, one of these templates, app-template, has been modified so the output apps are built with vite. But addon-template hasn't been modified the same way. With the work on virtualization, we start to see test cases where we require the addon-template to output a dummy app building with vite as well.

This PR aligns addon-template with app-template to use vite:

• aligns the dependencies
• aligns vite and babel configs (+ ignores prettier)
• change the test so there's no helper to be discovered at runtime (this no longer work because vite build use staticHelpers)

[mansona]

LGTM 💪