Consider moving views to a separate folder under src

[kungpaogao]

I think it would be helpful to separate out views (pages) to a separate folder, so it's easier for developers. Views should be the Vue components that are referenced by the router.

What I mean:

src
|- views
  |- Login.vue
  |- other pages ...
|- components
  |- Course.vue
  |- Card.vue
  |- other components ...

This is loosely based off the project structure of Nuxt.js: https://nuxtjs.org/guide/directory-structure