Rename conflicting params

[ankke]

To avoid naming conflict for some of the models lags param is renamed to n_lags. Now, n_lags param is used for pipeline configuration and should be equal to the model parameter specifying number of lags (depending on the model i.e. input_chunk_length or lags).

Similarly param model is now renamed to darts_model.

[codecov]

Codecov Report

Merging #55 (340ec32) into main (f6df00b) will increase coverage by 0.01%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##             main      #55      +/-   ##
==========================================
+ Coverage   87.22%   87.23%   +0.01%     
==========================================
  Files          33       33              
  Lines        2215     2217       +2     
==========================================
+ Hits         1932     1934       +2     
  Misses        283      283              

Impacted Files	Coverage Δ
tests/test_models.py	99.30% <ø> (ø)
tests/test_plotting.py	95.83% <ø> (ø)
tests/test_processing_panel_data.py	94.50% <ø> (ø)
tot/experiment.py	94.19% <100.00%> (ø)
tot/models/models_darts.py	86.74% <100.00%> (+0.32%)	⬆️