Add inverse_transform in *OutliersTransform

[WinstonDovlatov]

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• Examples / docs / tutorials / contributors update
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Related Issue

Closing issues

closes #129

[codecov-commenter]

Codecov Report

Merging #160 (f442b68) into master (aa463ed) will decrease coverage by 0.14%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master     #160      +/-   ##
==========================================
- Coverage   87.42%   87.27%   -0.15%     
==========================================
  Files          73       74       +1     
  Lines        3164     3286     +122     
==========================================
+ Hits         2766     2868     +102     
- Misses        398      418      +20     

Impacted Files	Coverage Δ
etna/transforms/outliers.py	98.61% <100.00%> (+0.33%)	⬆️
etna/analysis/plotters.py	12.90% <0.00%> (-0.67%)	⬇️
etna/models/prophet.py	98.18% <0.00%> (-0.52%)	⬇️
etna/datasets/tsdataset.py	86.43% <0.00%> (-0.51%)	⬇️
etna/models/base.py	97.46% <0.00%> (ø)
etna/analysis/__init__.py	100.00% <0.00%> (ø)
etna/transforms/__init__.py	100.00% <0.00%> (ø)
etna/transforms/stl.py	93.10% <0.00%> (ø)

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[julia-shenshina]

Update CHANGELOG.md please