Separate cluster management and mastership management to separate packages

Change-Id: If1e399648451842da6dccc644b75b81337b105f9
diff --git a/core/api/src/main/java/org/onlab/onos/mastership/MastershipTermService.java b/core/api/src/main/java/org/onlab/onos/mastership/MastershipTermService.java
new file mode 100644
index 0000000..567962e
--- /dev/null
+++ b/core/api/src/main/java/org/onlab/onos/mastership/MastershipTermService.java
@@ -0,0 +1,20 @@
+package org.onlab.onos.mastership;
+
+import org.onlab.onos.net.DeviceId;
+
+// TODO give me a better name
+/**
+ * Service to obtain mastership term information.
+ */
+public interface MastershipTermService {
+
+    // TBD: manage/increment per device mastership change
+    //      or increment on any change
+    /**
+     * Returns the term number of mastership change occurred for given device.
+     *
+     * @param deviceId the identifier of the device
+     * @return current master's term.
+     */
+    MastershipTerm getMastershipTerm(DeviceId deviceId);
+}