Feature/refactor model checker

[TsumiNa]

• Remove datatool.Storage class and it's testing
• Increment=True do not keep the persisted files non-overlapping

[codecov[bot]]

Codecov Report

Merging #134 into develop will decrease coverage by 0.42%. The diff coverage is 77.2%.

@@             Coverage Diff             @@
##           develop     #134      +/-   ##
===========================================
- Coverage    77.38%   76.96%   -0.43%     
===========================================
  Files           89       87       -2     
  Lines         5373     5174     -199     
===========================================
- Hits          4158     3982     -176     
+ Misses        1215     1192      -23

Impacted Files	Coverage Δ
xenonpy/model/training/predictor.py	27.77% <0%> (ø)	:arrow_up:
xenonpy/datatools/__init__.py	100% <100%> (ø)	:arrow_up:
xenonpy/datatools/mdl.py	95.52% <100%> (+0.06%)	:arrow_up:
xenonpy/model/training/extension/validator.py	47.91% <100%> (+1.1%)	:arrow_up:
xenonpy/datatools/dataset.py	97.77% <100%> (+0.02%)	:arrow_up:
xenonpy/datatools/transform.py	85.91% <100%> (+0.09%)	:arrow_up:
tests/models/test_extension.py	97.88% <100%> (ø)	:arrow_up:
tests/models/test_base_runner.py	98.75% <100%> (+0.03%)	:arrow_up:
xenonpy/datatools/preset.py	92.23% <100%> (+0.07%)	:arrow_up:
tests/models/test_checker.py	98.27% <100%> (-0.03%)	:arrow_down:
... and 6 more

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