Uploading a large WARC does not provide any indication to wait or show progress

[machawk1]

When uploading a large WARC (I tested w/ the one link in the OP @ #828), the browser tab's "busy" indicator spins but the interface does not change after the Upload button is pressed. At a minimum, we ought to show that the WARC has been submitted and is being uploaded, perhaps allowing the user to still interface with the interface (i.e., no modal). Even better would be to show progress, but that would require async communication of the web interface w/ the indexer.