[fluentd-elasticsearch] Allow multiple hosts in config

[samuel-begin]

FEATURE REQUEST

Since Fluentd config accepts multiple hosts in its config, I would like to be able to provide them through the chart.

So migrating the parameter:

Parameter	Description	Default
elasticsearch.host	Elasticsearch Host	elasticsearch-client

to:

Parameter	Description	Default
elasticsearch.hosts[]	Elasticsearch Hosts list	[]

[samuel-begin]

I'll be working on this, since we need it for our deployment

Would you prefer to deprecate host and have migration doc? or you'd rather stay backwards compatible and have both parameters host and hosts[]?

[monotek]

I would prefer to deprecate host and have migration doc.