Update Instance details layout and display

[jarofmy]

https://portal.slateci.io/instances/instance_eXKOJ7K9EQk : It would be really helpful if the timestamps of the events were shown. The counts, on the other hand, can probably be hidden when they are 1 (which is frequent).

It would also be nice to have a clearer separation between the individual events, like there is for the containers in the adjacent column. (As it is, when I look in the middle of the long list its hard to tell which lines are asscoiated with the same event.)