WebUI: Adding Filters support to system logs

Adding Filter support to system logs page
 - Severity filter.
 - Date filter with start and end date.
 - Filter by Sensort Type.

Tested By:
  Loaded System logs page with type selection
  'Event' and check all filters.

Change-Id: I41eba4cd59c0f3c2933637bf0e207a3eca3214f1
Signed-off-by: AppaRao Puli <apparao.puli@linux.intel.com>
diff --git a/app/index.js b/app/index.js
index 3b1089d..38df0e9 100644
--- a/app/index.js
+++ b/app/index.js
@@ -75,6 +75,7 @@
 import log_controller from './server-health/controllers/log-controller.js';
 import sensors_overview_controller from './server-health/controllers/sensors-overview-controller.js';
 import syslog_controller from './server-health/controllers/syslog-controller.js';
+import syslog_filter from './common/directives/syslog-filter.js';
 
 import redfish_index from './redfish/index.js';
 import redfish_controller from './redfish/controllers/redfish-controller.js';