Remove collection perspective placeholders

src/client/components/main_layout/Main.js

@@ -60,11 +60,11 @@ let Main = props => {
       label: 'Manuscripts',
       desc: 'Physical manuscript objects.'
     },
-    {
-      id: 'collections',
-      label: 'Collections',
-      desc: ''
-    },
+    // {
+    //   id: 'collections',
+    //   label: 'Collections',
+    //   desc: ''
+    // },
     {
       id: 'works',
       label: 'Works',

src/client/components/main_layout/TopBar.js

@@ -74,7 +74,7 @@ class TopBar extends React.Component {
     const AdapterLink = React.forwardRef((props, ref) => <Link innerRef={ref} {...props} />);
     const AdapterNavLink = React.forwardRef((props, ref) => <NavLink innerRef={ref} {...props} />);
 
-    const perspectives = [ 'manuscripts', 'collections', 'works', 'events', 'actors', 'places' ];
+    const perspectives = [ 'manuscripts', 'works', 'events', 'actors', 'places' ];
 
     const renderMobileMenu = (
       <Menu