Superevent visual changes

Lots of visual improvements to superevents. Need to port to the public view.
2 jobs for gracedb-2.10.0-2 in 16 minutes and 54 seconds (queued for 1 second)
Status Job ID Name Coverage
  Test
passed #1077522
test:3.7

00:10:01

73.0%
 
  Branch
passed #1077523
branch_image

00:06:53