insights: revisit polling mechanism

[coury-clark]

Consider an alternative approach to polling for insight updates while they are processing. With the new backfiller system it may be much better to subscribe to the dashboard and watch for update events, only refreshing the charts when the refresh event is produced.

/cc @joelkw @felixfbecker @vovakulikov

[coury-clark]

p2

[vovakulikov]

@coury-clark do you mean here a real subscription system? like web-sockets or web streams? or is it something different?

[chwarwick]

p2