Adding health check endpoint to distribution

* Adding health check REST endpoint to distribution service.
* Adding isAlive field to DistributionActivator to fetch the health
  status.
* Adding parameter group for rest server parameters.
* Adding DistributionRestController for hosting all the rest endpoints
  in distribution service.
* Adding DistributionRestServer to manage lifecycle of distribution rest server.
* Adding ParameterValidationUtils utility class for common validations.
  Plan is to move this class to policy-common for wider use later.
* Adding test cases for all new code added.
* Refering common classes from policy/common

Change-Id: I246d57133ed1f0c3548bcdee173d7b64fb368abc
Issue-ID: POLICY-1035
Signed-off-by: ramverma <ram.krishna.verma@ericsson.com>
diff --git a/main/pom.xml b/main/pom.xml
index 468f3fe..e027e44 100644
--- a/main/pom.xml
+++ b/main/pom.xml
@@ -53,6 +53,16 @@
             <version>1.3.0-SNAPSHOT</version>
         </dependency>
         <dependency>
+            <groupId>org.onap.policy.common</groupId>
+            <artifactId>capabilities</artifactId>
+            <version>1.3.0-SNAPSHOT</version>
+        </dependency>
+        <dependency>
+            <groupId>org.onap.policy.common</groupId>
+            <artifactId>policy-endpoints</artifactId>
+            <version>1.3.0-SNAPSHOT</version>
+        </dependency>
+        <dependency>
             <groupId>commons-cli</groupId>
             <artifactId>commons-cli</artifactId>
         </dependency>