Clean up icons

Clean up duplicate svg icons from assets directory.
Created a statusIcon component to dynamically render
status icons instead of using background-image in
scss files.

- Moved/removed on, off, critical, warning svg icons from
  assets directory
- Updated background-image status icons to use <icon>
  or <status-icon> directive

Signed-off-by: Yoshie Muranaka <yoshiemuranaka@gmail.com>
Change-Id: Ic0f06d78b0861d6f60d40b2dcc0b80fd6dad2a88
diff --git a/app/server-health/controllers/inventory-overview-controller.html b/app/server-health/controllers/inventory-overview-controller.html
index c0f05d2..5dc6f03 100644
--- a/app/server-health/controllers/inventory-overview-controller.html
+++ b/app/server-health/controllers/inventory-overview-controller.html
@@ -45,7 +45,7 @@
             <div class="row column">
               <h5 class="small-12 content-label">Subcomponents</h5>
               <p ng-repeat="sub_component in inventory.sub_components" class="large-6 small-3 courier-bold" ng-if="sub_component.Present">
-                <span class="icon icon__warning" ng-if="!sub_component.Functional"></span>
+                <icon file="icon-warning" aria-hidden="true" ng-if="!sub_component.Functional"></icon>
                 {{sub_component.title}}
               </p>
             </div>