feat(navbar): add optional fixed parameter

Author: marie-j

packages/manager/modules/navbar/README.md

@@ -128,6 +128,17 @@ Indicate current universe
 }
 ```
 
+#### fixed position 
+
+Indicate if fixed position should be applied to component
+
+```js
+{
+  fixed: true
+}
+```
+
+
 ## Build
 
 ```sh

packages/manager/modules/navbar/src/template.html

@@ -1,7 +1,8 @@
 <oui-navbar
     class="flex-nowrap"
     data-brand="$ctrl.brand"
-    data-active-link="{{ :: $ctrl.navbarOptions.universe }}">
+    data-active-link="{{ :: $ctrl.navbarOptions.universe }}"
+    data-fixed="$ctrl.fixed">
     <oui-navbar-main>
         <oui-spinner data-size="s" data-ng-if="$ctrl.isLoading"></oui-spinner>
         <div