change output of how jobs are printed during poll stage

[shahzebsiddiqui]

Refactor batch executor class (slurm, lsf, cobalt)
print table of completed and pending jobs

[codecov]

Codecov Report

Merging #664 (b29cb06) into devel (dbddad0) will increase coverage by 6.83%.
The diff coverage is 60.73%.

@@            Coverage Diff             @@
##            devel     #664      +/-   ##
==========================================
+ Coverage   57.69%   64.52%   +6.83%     
==========================================
  Files          21       34      +13     
  Lines        1553     2816    +1263     
  Branches      226      516     +290     
==========================================
+ Hits          896     1817     +921     
- Misses        606      875     +269     
- Partials       51      124      +73     

Impacted Files	Coverage Δ
buildtest/log.py	63.16% <ø> (ø)
buildtest/executors/slurm.py	13.45% <13.45%> (ø)
buildtest/executors/cobalt.py	16.07% <16.07%> (ø)
buildtest/executors/lsf.py	16.67% <16.67%> (ø)
buildtest/buildsystem/compilerbuilder.py	24.35% <24.35%> (ø)
buildtest/menu/__init__.py	44.44% <34.78%> (+23.75%)	⬆️
buildtest/config.py	37.80% <35.44%> (-62.20%)	⬇️
buildtest/menu/compilers.py	37.96% <37.96%> (ø)
buildtest/executors/setup.py	44.32% <44.32%> (ø)
buildtest/menu/build.py	56.78% <54.92%> (+31.15%)	⬆️
... and 43 more

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