Avoid dedicated master nodes

[jimmyjones2]

As far as I can see, with a simple demo and running a standard config Elasticsearch, and one with:

node.master: true
node.data: false

the perl client will still send indexing requests to the dedicated master. Shouldn't this be avoided? This blog post says "By reducing the amount of resource intensive work that these nodes do (no data ingestion or search), we greatly reduce the chance of cluster instability.". The python client seems to avoid dedicated masters.

[ezimuel]

To be solved in #73.