[DOCS] Enable read-only access for kibana_system user (elastic/x-pack-elasticsearch#2465)
[DOCS] Enable read-only access for kibana_system user (elastic/x-pack-elasticsearch#2465)

Original commit: elastic/x-pack-elasticsearch@de586c2ce5acaba47e6d5a78ea00283504d7a1f5

vroyer/elassandra,strapdata/elassandra,vroyer/elassandra,vroyer/elassandra,strapdata/elassandra,strapdata/elassandra,strapdata/elassandra,strapdata/elassandra