Create releases/logsearch-9

Includes:

* #24 - Allow elasticsearch node tags 
* #20 - Pull in additional logstash filters from `tar/tar.gz/zip` urls defined in `logstash_parser.filters` array.  
* #18 - Formalise release process (`feature-branch` -> PR -> `develop`,  =merge=> `release-candidate` -> PR -> `master`)