Adds assocation and QOS limits for the pack job as a whole

Clear a job's "wait reason" value of BeginTime" after that time has
passed. Previously a readon of "BeginTime" could be reported long
after the job's requested begin time had passed (for so long as the
current reason is "None".

Add support to sched/backfill for concurrent allocation of all pack job
      components including support of --time-min option.

Fix for possible slurmctld abort with use of salloc/sbatch/srun
    --gres-flags=enforce-binding option.
bug 4008

Update from commit b40bd8d3

By removing the real locks we can get into a race condition where the prolog
starts and finishes before we get here and then we end up waiting forever.

Making the mutex a static seemed to help in many cases, but didn't
completely close the window.  Changing slurm_cond_wait to
slurm_cond_timedwait fixed the scenario where we would hit the window, but
not degrade performance the original commit provides.

There were also spots where if the job or step didn't exist it wouldn't
signal the conditional also providing a spot this could get stuck not
starting the job.

Fix regression from commit 52ce3ff0

Bug 3977

Avoid interleaving labels and output from various components of
   a pack job

Major re-write of task state container logic to support for list of
  containers rather than one container per srun command.

Modify all daemons to re-open log files on receipt of SIGUSR2 signal.  This
    is much than using SIGHUP to re-read the configuration file and rebuild
    various tables.
bug 3070

This is a regression from commit fec995e0.

It turns out using tok here was erroneous for situations where the gres had
a type and name and potentially a count (i.e. network:gigabit:1)

_get_gres_req_cnt() would alter the incoming char *config which is what tok
was.  So when we print it back to the requested string it would only have
what was there to the first ':'.  As we didn't need to \0 out the first char
as we skip over it anyway I just kept track of what the replaced \0 was for
the number portion and put it back when we are done copying it.

Related to bug 3521

No changes to logic

bug 3979

Bug 3967

Bug 3979 and 3989

This reverts commit d49081df.

Bug 3979 and 3989

Otherwise we can end up printing Start times greater than End times,
leading to confusion when reading sacct output. 0 is displayed as Unknown.
Cosmetic change.

Bug 3940.

This behavior was introduced in bug 2504, commit 7fb0c981 and bug 2643
commit 988edf12 respectively.

The reasoning is that sysadmins who see nodes with Reason "Not Responding"
but they can manually ping/access the node end up confused. That reason
should only be set if the node is trully not responding, but not if the
HealthCheckProgram execution failed or returned non-zero exit code. For
that case, the program itself would take the appropiate actions, such
as draining the node and setting an appropiate Reason.

Bug 3931

Bug 3957.

burst_buffer logic modified to support sizes in both SI and EIC size units
    (e.g. M/MiB for powers of 1024, MB for powers of 1000).
bug 3922

This patch removes a window in which a message bound for the DBD
could be packed with the non-dbd packing.  This would result in a
packed msg_type, but nothing else.  When that message was given to
the DBD it would complain forever about an unpacking error.

Bug 3891 and 3939

done.

Pretty much remove 10cc6f93

Bug 3919

workflows through the slurmd.

Bug 3833

Underlying logic not yet available, just the new option parsing and
  documentation.

from the slurmctld make sure the step allocation is made aware of it.

Bug 3926

Also see commit b30139e5