Redesign (#6080)

* [top bar, side panel] modified UI of the top bar; redesigned the side panel(moved the content in the bottom to the side nav)

* [font icons] updated the 'department' & 'invite Guest' icons

* [linked devices] moved it from the 'home' side panel to the 'settings' page

* ['settings' page] redesigned the empty tip for 'linked devices'

frontend/src/components/side-panel.js

@@ -2,7 +2,6 @@ import React from 'react';
 import PropTypes from 'prop-types';
 import Logo from './logo';
 import MainSideNav from './main-side-nav';
-import SideNavFooter from './side-nav-footer';
 
 const propTypes = {
   isSidePanelClosed: PropTypes.bool.isRequired,
@@ -22,9 +21,6 @@ class SidePanel extends React.Component {
         <div className="side-panel-center">
           <MainSideNav tabItemClick={this.props.tabItemClick} currentTab={this.props.currentTab} />
         </div>
-        <div className="side-panel-footer">
-          <SideNavFooter />
-        </div>
       </div>
     );
   }