Side nav (#6309)

* [user panel] combined 7 commits into 1:

[user side nav] added 'fold/unfold' for the sidebar

[redesign] redesigned toolbar for 'my libs' & 'shared with all'; redesigned 'top bar' for 'help', 'clients' and other pages

[Shared with all] 'share existing libraries' dialog: added the 'close' icon back, enabled clicking outside to close the dialog

['Invite Guest' page] redesigned the toolbar

['Share Admin' - 'Links'] 'Share Links' page: redesigned the toolbar

['Share Admin' - 'Links'] 'Upload Links' page: redesigned the toolbar

cleaned up code

* [user side panel] update

* [user panel] update

* [code style] update: remove an eslint warning

frontend/src/pages/libraries/index.js

@@ -242,8 +242,7 @@ class Libraries extends Component {
         <TopToolbar
           onShowSidePanel={this.props.onShowSidePanel}
           onSearchedClick={this.props.onSearchedClick}
-        >
-        </TopToolbar>
+        />
         <div className="main-panel-center flex-row">
           <div className="cur-view-container">
             <div className="cur-view-path">