feature: SSH-like repl direct to workers (ee)

[rubenfiszel]

For debugging purposes, it would be nice to be able to "connect in SSH" to a worker. The way it would be implemented is by having a listen/notify in workers that would only react to commands with the worker name and that would send individual bash snippets. The worker would respond to those individual commands by executing them as individual bash script. The frontend would make it SSH/REPL like.