Build the batch_job_launch_msg_t in one function so it can be used
to launch a new job via agent.c and another for use as a select/serial
batch job completion response

This eliminates one of four RPCs needed for each job.

Do not wait for slurmctld to request job termination

This will eventually permit the slurmctld to respond to the slurmd
with a new task launch RPC

This corrects some logging message headers, streamlines som ecode,
adds other comments, etc.

Start from select/cons_res and in the process of removing unused logic.

Cray - Add support for zero compute note resource allocation to run batch
script on front-end node with no ALPS reservation. Useful for pre- or post-
processing. NOTE: The partition must be configured with MinNodes=0.