Split cli.SubmitOpCode in two parts

The current SubmitOpCode function is not flexible enough to be used for
submitters that don't want to wait for the job finish.

The patch splits this in two, a SendJob function and a PollJob one, and
the old SubmitOpCode becomes a wrapper. Note that the new SendJob takes
a list of opcodes (and not a single opcode anymore).

Reviewed-by: imsnah