[ENH] EXPERIMENTAL: TFT model based on the new data pipeline

[phoeenniixx]

Description

This PR implements the tft model based on the new data pipeline. This PR is branched off from #1811

[codecov]

Codecov Report

Attention: Patch coverage is 1.82292% with 377 lines in your changes missing coverage. Please review.

Please upload report for BASE (main@e87230b). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
pytorch_forecasting/data/data_module.py	0.00%	157 Missing ⚠️
...els/temporal_fusion_transformer/tft_version_two.py	0.00%	77 Missing ⚠️
...rch_forecasting/models/base/base_model_refactor.py	0.00%	73 Missing ⚠️
pytorch_forecasting/data/timeseries.py	9.09%	70 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1812   +/-   ##
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  Coverage        ?   81.02%           
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  Files           ?       49           
  Lines           ?     5685           
  Branches        ?        0           
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  Hits            ?     4606           
  Misses          ?     1079           
  Partials        ?        0           

Flag	Coverage Δ
cpu	81.02% <1.82%> (?)
pytest	81.02% <1.82%> (?)

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