UI: Show date in event grid if time period is older than 30 minutes

[niemyjski]

Let's say you have high event volume, and you see an error in your logs and you know the time stamp. You filter to a time range and still have 45 events to look at. You end up opening 45 tabs just to validate the date. One could alternatively hover to see the whole date, but using the Time Ago pattern doesn't really scale when you have to reason across days (think 1am) or DST.