CLC-3188: LiveUpdates: Hit updated_feeds API earlier and more often

https://jira.media.berkeley.edu/jira/browse/CLC-3188

The UI now makes the updated feeds request at the given intervals after page load: 2s, 5s, 15s, and then every 60 seconds after that.
Merge pull request #2076 from chikoon/CLC-3188-hit-updated-feeds-more-often

CLC-3188: LiveUpdates: Hit updated_feeds API earlier and more often