Created MVP app cohesion, created sass structure, implemented base styling

Created MVP application cohesion between homepage, topbar, and views (chat, folder, doc)

Created Sass folder structure and stylesheets:
main.scss is imported via asset pipeline. main.scss defines color legend and imports individual style sheets:
  - base stylesheets (applicable to all pages): fonts.scss, box.scss, images.scss
  - stylesheets for specific pages: header.scss, home.scss, chat.scss, doc.scss, footer.scss