viaducc does not handle attach_console correctly

by default viaducc enable both attach_console and cancel_on_interrupt. An option was added to suppress cancel_on_interrupt with the intent to let the remote process continue running after the local submit process was terminated. This was misguided because in many cases the remote process will terminate when it's stdout/stderr pipes were broken.

The new change makes attach_console an option, which in addition sets cancel_on_interrupt. The result is that by default viaducc will only monitor the DUCC state of the remote process and the remote process will not be terminated if the local submitter is stopped.