Support for ingest pipeline

[onnheimm]

Since Elastic 5, elasticsearch offers ingestion pipelines directly in elasticsearch https://www.elastic.co/guide/en/elasticsearch/reference/master/ingest.html

For some use cases it would be useful to enable access to this directly from a log handler, e.g. for augmenting wsgi logs with geoip without needing to go through a filebeat/logstash instance.

[cmanaha]

Thanks a lot for the feedback!

Absolutely. I have not had time in a long time to work on this and will gladly accept pull requests or even follow forks that have implementations and merge the implementation as long as provides all the testing and coverage. I've