[CORD-313] Handles uncaught exceptions when device is not configured

Includes following minor changes
    - Move DeviceConfiguration and DeviceProperties to config package
    - Create DeviceConfigNotFoundException

Change-Id: I32455d88c712bb65cd7f71dab9472ae003303de2
diff --git a/src/main/java/org/onosproject/segmentrouting/PolicyHandler.java b/src/main/java/org/onosproject/segmentrouting/PolicyHandler.java
index 83cb7e8..0a4c26d 100644
--- a/src/main/java/org/onosproject/segmentrouting/PolicyHandler.java
+++ b/src/main/java/org/onosproject/segmentrouting/PolicyHandler.java
@@ -27,6 +27,7 @@
 import org.onosproject.net.flowobjective.DefaultForwardingObjective;
 import org.onosproject.net.flowobjective.FlowObjectiveService;
 import org.onosproject.net.flowobjective.ForwardingObjective;
+import org.onosproject.segmentrouting.config.DeviceConfiguration;
 import org.onosproject.store.service.EventuallyConsistentMap;
 import org.slf4j.Logger;