limit amount of pins on desktop to 6 (for now)

src/components/nav_panel/nav_panel.vue

@@ -5,7 +5,7 @@
         v-if="!forceExpand"
         class="panel-heading"
       >
-        <NavigationPins />
+        <NavigationPins :limit="6" />
         <div class="spacer"/>
         <button
           class="button-unstyled"

src/components/navigation/navigation_pins.js

@@ -28,6 +28,7 @@ library.add(
   faList
 )
 const NavPanel = {
+  props: ['limit'],
   computed: {
     getters () {
       return this.$store.getters
@@ -67,7 +68,7 @@ const NavPanel = {
           isPrivate: this.privateMode,
           currentUser: this.currentUser
         }
-      )
+      ).slice(0, this.limit)
     }
   }
 }