optimised overview data api

app/controllers/ClusterOverviewController.scala

app/models/ShardStats.scala

app/models/commons/NodeRoles.scala

app/models/overview/ClosedIndices.scala

app/models/overview/ClusterOverview.scala

app/models/overview/Index.scala

app/models/overview/Node.scala

app/services/overview/ClusterOverview.scala

app/services/overview/DataService.scala

app/services/overview/Index.scala

app/services/overview/Node.scala

app/util/DataSize.scala

public/js/app.js

public/overview.html

public/stats.html

src/app/components/overview/controller.js

src/app/shared/index_filter.js

src/app/shared/node_filter.js

test/controllers/OverviewControllerSpec.scala

test/models/overview/ClusterInitializingShards.scala