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/sensors-overview-controller.html b/app/server-health/controllers/sensors-overview-controller.html
index 6f2b2d2..c65a9dd 100644
--- a/app/server-health/controllers/sensors-overview-controller.html
+++ b/app/server-health/controllers/sensors-overview-controller.html
@@ -57,7 +57,10 @@
     <tbody class="sensors__tbody">
       <tr class="sensors__tbody-row" ng-repeat="sensor in data|filter:filterBySeverity|filter:filterBySearchTerms|orderBy:'+custom_order' as filteredSensorData">
         <th class="sensors__tbody-header">
-          <span class="icon" ng-class="{'icon__critical': sensor.status == 'critical', 'icon__warning': sensor.status == 'warning', 'icon__normal': sensor.status == 'normal'}" aria-label="Sensor status: {{sensor.status}}" ></span>
+          <status-icon status="{{ sensor.status == 'critical' ? 'error' :
+                                  sensor.status == 'warning' ? 'warn' : null }}"
+                       aria-label="Sensor status: {{sensor.status}}">
+          </status-icon>
           <span>{{sensor.title}}</span>
         </th>
         <td class="sensors__tbody-cell">