Minor refactors - cleaning models

[akihironitta]

What does this PR do?

Closes #519 and closes #476.

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[codecov]

Codecov Report

Merging #524 (b8d4c7b) into master (55ab214) will decrease coverage by 1.63%.
The diff coverage is 70.88%.

@@            Coverage Diff             @@
##           master     #524      +/-   ##
==========================================
- Coverage   79.16%   77.53%   -1.64%     
==========================================
  Files         114      114              
  Lines        6466     6664     +198     
==========================================
+ Hits         5119     5167      +48     
- Misses       1347     1497     +150     

Flag	Coverage Δ
cpu	25.80% <36.36%> (-0.43%)	⬇️
pytest	25.80% <36.36%> (-0.43%)	⬇️
unittests	77.01% <64.55%> (-1.67%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
pl_bolts/models/gans/dcgan/dcgan_module.py	97.24% <ø> (+0.02%)	⬆️
pl_bolts/models/rl/dqn_model.py	78.48% <0.00%> (-0.50%)	⬇️
pl_bolts/transforms/dataset_normalizations.py	85.00% <ø> (+0.78%)	⬆️
pl_bolts/__init__.py	90.00% <33.33%> (-10.00%)	⬇️
pl_bolts/callbacks/vision/confused_logit.py	21.91% <33.33%> (-55.01%)	⬇️
...bolts/transforms/self_supervised/ssl_transforms.py	95.34% <33.33%> (-4.66%)	⬇️
pl_bolts/models/rl/common/gym_wrappers.py	85.49% <45.45%> (-6.11%)	⬇️
pl_bolts/models/rl/reinforce_model.py	88.61% <50.00%> (-0.73%)	⬇️
...l_bolts/models/rl/vanilla_policy_gradient_model.py	95.49% <50.00%> (+1.85%)	⬆️
...l_bolts/models/self_supervised/amdim/transforms.py	92.94% <50.00%> (-1.11%)	⬇️
... and 26 more

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[akihironitta]

@Borda I included some additional refactors as suggested in #476, and this PR should be ready to go. Please have a look :)

[Borda]

there an advantage or using "no cover" compare to "no-cover" I was thinking that the joined form is more like a tag :]