Create basic "select language" landing page

[jackieo5023]

Design

In App.jsx, we'll want to have some logic that goes like this: If a language is selected, do not show the landing page (aka everything under Router in this case). Otherwise, show the landing page (a new component you create).

To detect if a language is selected, simply do localStorage.getItem('language') !== null. We store the currently selected language in local storage - so if a language (say, Spanish) is selected, localStorage.getItem('language) would return "Spanish".

This new component you create can just have some basic buttons for all of the languages - no need to style it or implement functionality yet (unless you want to, but I'll probably create another issue for this). And maybe the purple background :)