Add TabularForecaster task based on PyTorch Forecasting

[sumanmichael]

What does this PR do?

Integrating https://github.com/jdb78/pytorch-forecasting into tabular/forecasting

Fixes #528 #529 #530 #531 #532

Before submitting

• Was this discussed/approved via a Github issue? (no need for typos and docs improvements)
• Did you read the contributor guideline, Pull Request section?
• Did you make sure your PR does only one thing, instead of bundling different changes together?
• Did you make sure to update the documentation with your changes?
  Documentation to come in a follow-up
• Did you write any new necessary tests? [not needed for typos/docs]
• Did you verify new and existing tests pass locally with your changes?
• If you made a notable change (that affects users), did you update the CHANGELOG?

PR review

• Is this pull request ready for review? (if not, please submit in draft mode)

Anyone in the community is free to review the PR once the tests have passed.
If we didn't discuss your PR in Github issues there's a high chance it will not be merged.

Did you have fun?

Make sure you had fun coding 🙃

[codecov]

Codecov Report

Merging #647 (d005bb1) into master (ddd4c94) will decrease coverage by 3.76%.
The diff coverage is 89.26%.

@@            Coverage Diff             @@
##           master     #647      +/-   ##
==========================================
- Coverage   89.01%   85.25%   -3.77%     
==========================================
  Files         230      237       +7     
  Lines       12720    12884     +164     
==========================================
- Hits        11323    10984     -339     
- Misses       1397     1900     +503     

Flag	Coverage Δ
unittests	85.25% <89.26%> (-3.77%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
...ore/integrations/pytorch_forecasting/transforms.py	33.33% <33.33%> (ø)
flash/tabular/forecasting/model.py	85.00% <85.00%> (ø)
...h/core/integrations/pytorch_forecasting/adapter.py	91.66% <91.66%> (ø)
flash/tabular/forecasting/data.py	95.00% <95.00%> (ø)
flash/core/data/data_pipeline.py	95.11% <100.00%> (-0.13%)	⬇️
.../core/integrations/pytorch_forecasting/__init__.py	100.00% <100.00%> (ø)
...core/integrations/pytorch_forecasting/backbones.py	100.00% <100.00%> (ø)
flash/core/utilities/imports.py	90.97% <100.00%> (+0.06%)	⬆️
flash/core/utilities/providers.py	100.00% <100.00%> (ø)
flash/tabular/__init__.py	100.00% <100.00%> (ø)
... and 19 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ddd4c94...d005bb1. Read the comment docs.

[review-notebook-app]

Check out this pull request on 

See visual diffs & provide feedback on Jupyter Notebooks.

---

Powered by ReviewNB

[Borda]

it is huge, from top level screening it looks good :]