Progress bars when uploading to Swarm

[adamschmideg]

A frontend to display these progress bars for a file

1. stored to localstore
2. sent for syncing
3. acknowledged as synced (fixes Progress bar for syncing #460)

[nolash]

@adamschmideg is this really priority for stability?

[adamschmideg]

I'm not sure, but @zelig seems positive about it. I hope he can give us more insights.

[zelig]

delivered in #1649