cmd/swarm: remove --no-track, add --progress flag

[nonsense]

If the API pointed to by swarm up doesn't support pushsync and the user hasn't added --no-track, we currently get an error:

[lash@furioso tmp]$ swarm --bzzapi https://swarm-gateways.net up photo_2019-10-02_10-10-59.jpg 
Fatal: failed to get tag data for hash: unexpected HTTP status: 404 Not Found

Even with session affinity, the progress bar doesn't work with pullsync (default Swarm configuration) today.

This PR is fixing this problem by falling back to swarm up functionality, which just displays the hash of the upload. If the user knows that the API supports pushsync, they can use --progress to see the progress bar.

[skylenet]

The 404 is because the swarm-gateways.net requests are load balanced. It uses a cookie to persist the session. If you don't reuse that cookie on the upcoming requests, you'll end up on another node, that doesn't know about the tag.

[janos]

With #1851 and bac377d uploads on public gateway work fine without changes to cli options.

[nonsense]

@janos we also found a bug with the progress bar and an encrypted upload.

I think the new swarm up functionality is not stable enough, so that we have it as a default, I'd rather we enable it behind a flag, similar to the --sync-mode=push we have right now, until it is stable.

[acud]

@nonsense you'll need to remove the --no-track flags i added across tests in order to generate machine readable output (see travis)

[janos]

This is the best option that we can do now.

[nonsense]

@janos @acud seeing that all tests were modified with --no-track should have triggered a warning for us to check the default behaviour of swarm up without additional flags :)