Add full SPA template to the CLI

[mrleblanc101]

Currently, configuring Nuxt to full SPA is more complicated than in the Nuxt 2 days. In nuxt 2:

ssr: false

But in nuxt 3, there is more configuration needed which cause confusion because it's not as clear as it was before:

ssr: false,
hooks: {
    'prerender:routes'({ routes }) {
        // Do not generate any routes except:
        // index.html
        // 200.html
        // 400.html
        // spa-loading-template.html
        routes.clear();
    },
},

So it would be nice to ask the rendering mode in the CLI like in the old [email protected] days: