Bug 17255 - Upgrade Elastic Search code to work with version 5.1

Bug 17255 - Upgrade Elastic Search code to work with version 5.1

Builds on top of commit:
    Bug 17255 - Upgrade Elastic Search code to work with version 2.4+ - rebased wip

-Fix data type 'string' to 'keyword' and 'text'
-index: not_analyzed deprecated, replaced with type: keyword which is equivalent
-store: yes was deprecated, use store: true

TODO: Installer bindings to both the debian package install and the raw developer install.
A taster in Buug 17851

ZE TEST PLAN

0. Remove existing ES and reinstall ES 5.1
   apt-get purge elasticsearch
   Follow instruction here:
   https://www.elastic.co/guide/en/elasticsearch/reference/current/deb.html

1. Reset Elasticsearch index since facets are hard coded to dynamic search_marc_mappings.
1a. perl -e 'use Koha::SearchEngine::Elasticsearch; Koha::SearchEngine::Elasticsearch->reset_elasticsearch_mappings();'
1b. If you get trouble, simply DELETE FROM [search_fields|search_marc_to_fields|search_marc_mapping];
    and retry 1a.
1c. Destroy elasticsearch index
    curl -XDELETE localhost:9200/koha_biblios
    so it can be recreated

2. Recreate the index:
   perl misc/search_tools/rebuild_elastic_search.pl
2a. Add something to index if your koha.biblio-table is empty

3. Fetch all indexed records and the facet for subject__facet

curl -XGET localhost:9200/koha_biblios/data/_search?pretty -d '{
  "aggregations": {
    "my_agg": {
      "terms": {
        "field": "subject__facet"
      }
    }
  }
}'

4. Run the included tests:
   perl t/db_dependent/Koha_Elasticsearch_Indexer.t
   perl t/db_dependent/Koha_Elasticsearch.t
   perl t/db_dependent/Koha_SearchEngine_Elasticsearch_Search.t

Have fun with your new ES 5.1 cluster!

Signed-off-by: Nick Clemens <nick@bywatersolutions.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Kyle M Hall <kyle@bywatersolutions.com>