Elasticsearch package/job cleanup...

 * drop HQ/marvel/jetty from pre-installed elasticsearch plugins
 * convert elasticsearch config from JSON to YAML
 * adding user-configurable elasticsearch.config_options, elasticsearch.logging_options  properties
Comment out restorer job in bosh-lite
Add elasticsearch.plugins property to support installing external plugins

    elasticsearch.plugins:
      - { "kopf" : "lmenezes/elasticsearch-kopf" }
      - { "HQ" : "https://github.com/royrusso/elasticsearch-HQ/zipball/master" }
      - { "marvel" : "elasticsearch/marvel/latest" }