[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
6 files changed
tree: a018595b5ff75279a86cfa4ad28b22896d1bc2a5
  1. BUCK
  2. app.xml
  3. features.xml
  4. pom.xml
  5. src/