add isort support with black profile

[kptkin]

Description

What does the PR do?

This PR introduced the isort lint tool that sorts all the imports according to the black style.
This PR remove the flake8-import-order plugging since it doesn't support black style and isort already provides both checks and ability to re-format the code.

This PR also re-formatted all the files in the repo except from the following:

• wandb/vendor
• wandb/proto
• wandb/__init__.py <- formatting this caused some breakage, so i'm leaving it for future work

Testing

How was this PR tested?

This PR is just reformat, ideal if everything done correctly all the test should pass

[codecov]

Codecov Report

Merging #4136 (9eb9a93) into master (117c48d) will decrease coverage by 0.01%.
The diff coverage is 92.21%.

@@            Coverage Diff             @@
##           master    #4136      +/-   ##
==========================================
- Coverage   82.72%   82.71%   -0.01%     
==========================================
  Files         256      256              
  Lines       32576    32534      -42     
==========================================
- Hits        26950    26912      -38     
+ Misses       5626     5622       -4     

Flag	Coverage Δ
functest	55.01% <75.14%> (-0.05%)	⬇️
unittest	73.47% <76.34%> (-0.03%)	⬇️

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

Impacted Files	Coverage Δ
wandb/apis/reports/blocks.py	100.00% <ø> (ø)
wandb/data_types.py	82.65% <ø> (ø)
wandb/filesync/dir_watcher.py	87.76% <ø> (ø)
wandb/filesync/step_prepare.py	94.93% <ø> (ø)
wandb/filesync/step_upload.py	95.04% <ø> (ø)
wandb/integration/catboost/catboost.py	90.56% <ø> (ø)
wandb/integration/kfp/kfp_patch.py	83.33% <ø> (ø)
wandb/integration/sacred/__init__.py	55.31% <ø> (ø)
wandb/integration/sb3/sb3.py	82.14% <ø> (ø)
wandb/integration/tensorboard/monkeypatch.py	90.12% <ø> (-2.47%)	⬇️
... and 163 more

[raubitsj]

GREAT!