Hide list of files during upload, display progress bar instead

[ratermir]

Enhancement: The component works well - thank you for developing it, butI'd have some proposal for UI/UX improvement:

I sugest to change the behavour and screen layou the way, that list of files would be hidden by default, instead of it there will be upload summary (total files count, total upliad size ...) and progress bar that would respect current percentage od upload done (either by files count or files size - the size is better I guess ...), time estimation ... etc.

The reason for this request is that if there is a plenty of files to upload (which - I guess - is the case why the component was created; in my case around 7000 files), the page drastically slows down with the full file list (sometimes froze comletly), also memory consumption and processor utilization are very high. Also the continuous screen the big list update and screen refresh slows down the overall upload process.
Moreover the list of individual files tells nothing obout overall upload status.

The full file list could be available on demand - by pressing on the separate button (and the HTML visual form could be generated at the press moment).

It partially relates to the issue #194

[JonathanTreffler]

Very good idea :)