Status is inaccurate in ImportRecords UI and timing is misleading

[kevinrobinson]

re: status

A job that's in the middle of running will show "Job completed in 25 minutes" even though it's still working (the "log" in the UI corroborates this, aside from the real logs). First seen on record 1653.

re: timing

ImportTask includes some indexing tasks in addition to individual importers, but these aren't considered in the time shown (or in the text describing whether the job is done or not). Depending on the options, this can hide ~15min of the time for the job, and make it look like the job is complete when it's actually still running. It looks like this time might be being computing based on the line-by-line times instead of the actual time the job took to run. See Somerville record 1624 as a test case, the UI shows 35 minutes, but it actually took 42 minutes.

There may be rounding errors here too - see the Somerville job starting "2018-07-10T04:01:21" that shows as "1 hour" in the UI as record 1655 but the importer classes actually took 87 minutes (96 with the tasks at the end).