Upload progress bar now displays informations about uploads...

... uploades size (e.g. 12kB of 3MB) and the current speed.

Making this PR for this: #8105 

Here is a live test:
user: test
pw: bla
http://flutterb.at/owncloud-testserver

should replace https://github.com/owncloud/core/pull/10324
@LukasReschke @wakeup 
for the line below, I don't see why we should localize "/s" as in MB/s, when the MB comes form humanFileSize() which seems not to have translations, or am I wrong here?