[CORD-2486] Improve Mcast CLI APIs

It adds following commands:
- sr-mcast-tree which shows the mapping group-tree
- sr-mcast-next which shows the mapping device-next
- mcast-routes which is similar to the unicast command (routes)

It improve following commands:
- mcast-join adds completer and improves output
- mcast-delete adds completer and improves output
- mcast-show improves output and adds completer

Change-Id: I4e273ac23b05142026b6b77317b0c9b7af76c3ec
diff --git a/apps/segmentrouting/src/main/resources/OSGI-INF/blueprint/shell-config.xml b/apps/segmentrouting/src/main/resources/OSGI-INF/blueprint/shell-config.xml
index 56b6f43..cfd7502 100644
--- a/apps/segmentrouting/src/main/resources/OSGI-INF/blueprint/shell-config.xml
+++ b/apps/segmentrouting/src/main/resources/OSGI-INF/blueprint/shell-config.xml
@@ -69,10 +69,26 @@
         <command>
             <action class="org.onosproject.segmentrouting.cli.LinkStateCommand"/>
         </command>
+        <command>
+            <action class="org.onosproject.segmentrouting.cli.McastNextListCommand"/>
+            <completers>
+                <ref component-id="mcastGroupCompleter"/>
+                <ref component-id="nullCompleter"/>
+            </completers>
+        </command>
+        <command>
+            <action class="org.onosproject.segmentrouting.cli.McastTreeListCommand"/>
+            <completers>
+                <ref component-id="mcastGroupCompleter"/>
+                <ref component-id="nullCompleter"/>
+            </completers>
+        </command>
     </command-bundle>
 
+    <bean id="nullCompleter" class="org.apache.karaf.shell.console.completer.NullCompleter"/>
     <bean id="deviceIdCompleter" class="org.onosproject.cli.net.DeviceIdCompleter"/>
     <bean id="pseudowireIdCompleter" class="org.onosproject.segmentrouting.cli.PseudowireIdCompleter"/>
+    <bean id="mcastGroupCompleter" class="org.onosproject.cli.net.McastGroupCompleter"/>
 
 </blueprint>