Requests for reports page

A while back I set up the beta reports page on gracedb-playground that just showed the upload latency for all g-events uploaded to GraceDB over the last seven days. I had it up and running and had thrown it out in various telecons, but never received feedback from it. I saw @rebecca.ewing using it during this morning's gstlal review call! I'm going to use this ticket to solicit requests for new features. I'm thinking:

• Variable date range (specify start and end times to make the query)
• Filter Early Warning events on/off or on a separate plot
• For superevents, plot time when GCN_PRELIM_SENT label applied less, the t_0 of the superevent. Come up with a name for this parameter? time_to_alert?
• Plot time_to_alert vs number of g-events for a superevent? Something like mean and stddev.