feat: add continuous prediction to output conversion

[Gerhardsa0]

Closes #740

Summary of Changes

I added a continues prediction for time series.

As example w.o. continues:
we want to predict values with forecast horizon 3, we only predict one value with 3 steps into the future.
With continues, all values until the forecast horizon (forecast horizon is included) will be predicted. This brought one problem up, as we don't store list values in our Columns. So I decided to make a new column for every step in the forecast horizon.
so with 3 there will be 3 prediction columns: prediction 0, prediction 1, prediction 2

Any Ideas on this behavior? @lars-reimann @Marsmaennchen221 @sibre28

[github-actions]

🦙 MegaLinter status: ✅ SUCCESS

Descriptor	Linter	Files	Fixed	Errors	Elapsed time
✅ PYTHON	black	5	0	0	0.96s
✅ PYTHON	mypy	5		0	2.74s
✅ PYTHON	ruff	5	0	0	0.3s
✅ REPOSITORY	git_diff	yes		no	0.46s

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (0564b52) to head (94ee24d).

Additional details and impacted files

@@            Coverage Diff            @@
##              main      #741   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files           79        79           
  Lines         5848      5858   +10     
=========================================
+ Hits          5848      5858   +10     

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[lars-reimann]

The upcoming polars-based implementation allows storing lists inside of columns. See the experimental tabular containers.