Robust progress bars

[gordonwatts]

The polling frequency between transform and minio cause some weird discrepancies

• Poll serviceX and when the number of files changes there check with minio

We've seen the following cases:

1. DID finder is complete but the serviceX bar still shows 0/? Only seen with large number of files
2. ServiceX shows the wrong number as the total files (less than the actual number)

Progress bar must not be red during successful runs

[kyungeonchoi]

Celery improvements of backend may solve this issue

[ponyisi]

"Progress bar going red for successful transforms" is fixed (actually we have the inverse problem now, the bar for a transform only goes red at the very end when there are failed files, not when the first failed file is detected)