Consider using vitest, rather than jest

[sandbergja]

Figgy, Allsearch-frontend, Tigerdata, and Marquand catalogs are all using vitest. Maybe lux-styleguidist should match.

One benefit of using vitest is that it uses vite to compile the components, which we also use for packaging lux-styleguidist. That way, we could use the same tools for testing and packaging lux.

Another benefit is that we could move away from using vue-cli to run our tests. This would be good because vue-cli is in maintenance mode and Vue recommends using vitest instead.