Remove Cobalt support

[al-rigazzi]

With the retirement of Theta, we are not aware of any other system using Cobalt as a workload manager. Therefore, this PR removes support for Cobalt.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (f683521) 90.34% compared to head (51715d7) 90.80%.

Additional details and impacted files

@@             Coverage Diff             @@
##           develop     #448      +/-   ##
===========================================
+ Coverage    90.34%   90.80%   +0.46%     
===========================================
  Files           60       60              
  Lines         3833     3830       -3     
===========================================
+ Hits          3463     3478      +15     
+ Misses         370      352      -18     

Files	Coverage Δ
smartsim/_core/control/controller.py	87.20% <100.00%> (+0.32%)	⬆️
smartsim/_core/control/manifest.py	96.25% <100.00%> (+2.50%)	⬆️
smartsim/_core/launcher/__init__.py	100.00% <ø> (ø)
smartsim/_core/launcher/step/__init__.py	100.00% <ø> (ø)
smartsim/_core/launcher/step/mpiStep.py	88.88% <100.00%> (ø)
smartsim/_core/launcher/stepInfo.py	100.00% <ø> (ø)
smartsim/database/orchestrator.py	86.85% <ø> (ø)
smartsim/entity/dbobject.py	65.13% <100.00%> (ø)
smartsim/experiment.py	85.62% <100.00%> (+0.28%)	⬆️
smartsim/log.py	93.63% <100.00%> (ø)
... and 3 more

... and 5 files with indirect coverage changes

[MattToast]

Everything seems to LGTM!!

[ashao]

Looks good! The only suggestion, which may have been discussed while I was away, is to throw a more informative error if someone specifically tried to request the cobalt launcher. I wouldn't even give it it's own dummy class, just throw it on the instantiation of Experiment, i.e.

if launcher == "cobalt":
  raise SSUnsupportedError("Support for the Cobalt launcher is no longer supported")

[al-rigazzi]

Looks good! The only suggestion, which may have been discussed while I was away, is to throw a more informative error if someone specifically tried to request the cobalt launcher. I wouldn't even give it it's own dummy class, just throw it on the instantiation of Experiment, i.e.

if launcher == "cobalt":
  raise SSUnsupportedError("Support for the Cobalt launcher is no longer supported")

Slightly reworded and added to Experiment. Added a test.