Add a "ssl_certificate_verification" field to Logstash's Elasticsearch Filter

[tinytwo]

We know that both logstash-input-elasticsearch and logstash-output-elasticsearch support the ability to disable ssl certificate verification with the use of ssl_certificate_verification: false.

In certain dev environments it has come in handy -- I'd like to request adding this option to logstash-filter-elasticsearch as well.

Related issue:

• Disable ssl certificate validation logstash-input-elasticsearch#33

Related documentation:

• https://www.elastic.co/guide/en/logstash/current/plugins-inputs-elasticsearch.html#plugins-inputs-elasticsearch-ssl_certificate_verification
• https://www.elastic.co/guide/en/logstash/current/plugins-outputs-elasticsearch.html#plugins-outputs-elasticsearch-ssl_certificate_verification