ACCUMULO-3147 Refactor ReplicationTable constants
ACCUMULO-3147 Create replication table at initialize, upgrade

  Migrate to all replication code to a built-in system-managed replication
  table instead of the user-space one. Ensure all replication-related tests
  pass. Also fix a small bug in Mock which threw an exception when using
  deleteRows with null start and end rows.
Merge remote-tracking branch 'origin/master' into ACCUMULO-3147
ACCUMULO-3147 Fix replication test bug

  Test was trying to talk to ZooKeeper for MockInstance
ACCUMULO-3147 Fix ReplicationServlet

  Properly show an informative banner message when the replication table is
  offline.
Merge remote-tracking branch 'origin/master' into ACCUMULO-3147
Merge branch 'ACCUMULO-3147'