Add DecisionData class and Explainability Extract article

[yusufuyanik1]

Now you can run decision analyzer app with the command pdstools run decision_analyzer. Health Check is same as before. DecisionData Class is added with plotting and aggregation function for analyzing the Explainability Extract and in the future Decision Analyzer dataset.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 22.20249% with 438 lines in your changes missing coverage. Please review.

Project coverage is 59.59%. Comparing base (7e0a0fd) to head (e4db776). Report is 14 commits behind head on master.

Files	Patch %	Lines
python/pdstools/decision_analyzer/plots.py	14.28%	156 Missing :warning:
python/pdstools/decision_analyzer/decision_data.py	29.18%	131 Missing :warning:
python/pdstools/decision_analyzer/utils.py	20.40%	78 Missing :warning:
...thon/pdstools/decision_analyzer/data_read_utils.py	16.86%	69 Missing :warning:
python/pdstools/pega_io/File.py	33.33%	4 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #226 +/- ## ========================================== - Coverage 66.13% 59.59% -6.55% ========================================== Files 24 29 +5 Lines 3222 3789 +567 ========================================== + Hits 2131 2258 +127 - Misses 1091 1531 +440 ```

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