SOLR-4792: remove empty webapp folder in dev-tools/maven

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1642464 13f79535-47bb-0310-9956-ffa450edef68
SOLR-6554: Add a ClusterState.copyWith method which accepts a collection directly instead of a map of collections and use it throughout

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1642466 13f79535-47bb-0310-9956-ffa450edef68