Controller process can be removed

[scherniavsky]

In order to simplify app's architecture, the controller process could be removed in favor of --no-web and --expect-slaves options.

[scherniavsky]

After deeper investigation, it turns out that some controller's features (e.g. spin up multiple slave processes, report extraction from a remote instance, files download) would require some kind of a controller process anyway. It should be possible to significantly simplify current implementation though.