Issue 1079: Add windowed features

[adamkells]

Implements the windowing of features. Relates to issue 1079.

Summary

Adds a function within RegressionModel to create new windowed features from a user dictionary which can contain either a user function or a string to implement a pre-defined function.

Other Information

[codecov-commenter]

Codecov Report

Base: 93.71% // Head: 93.15% // Decreases project coverage by -0.56% ⚠️

Coverage data is based on head (3bb7554) compared to base (8bb9959).
Patch coverage: 5.66% of modified lines in pull request are covered.

❗ Current head 3bb7554 differs from pull request most recent head 4ecc335. Consider uploading reports for the commit 4ecc335 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1203      +/-   ##
==========================================
- Coverage   93.71%   93.15%   -0.57%     
==========================================
  Files          83       83              
  Lines        8423     8463      +40     
==========================================
- Hits         7894     7884      -10     
- Misses        529      579      +50     

Impacted Files	Coverage Δ
darts/models/forecasting/regression_model.py	83.89% <5.66%> (-13.78%)	⬇️
darts/timeseries.py	91.96% <0.00%> (-0.07%)	⬇️
...arts/models/forecasting/torch_forecasting_model.py	87.45% <0.00%> (-0.05%)	⬇️
darts/models/forecasting/block_rnn_model.py	98.24% <0.00%> (-0.04%)	⬇️
darts/models/forecasting/nhits.py	99.27% <0.00%> (-0.01%)	⬇️
darts/datasets/__init__.py	100.00% <0.00%> (ø)

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.

[eliane-maalouf]

Hi @adamkells , thank you for submitting this draft PR for this improvement on features engineering. I am looking at it and updating it in those upcoming days.

[eliane-maalouf]

The history of this PR branch was merged with PR branch #1269.
It can be safely closed.

[hrzn]

Closing as commits have been brought to #1269