Backports for v0.16.0 (#3235)

*Description of changes:* Backporting PRs
- #3228 
- #3232 
- #3233 


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Ignore cpflows dependencies in test workflows, fix numpy 2 incompatib…

…ilities. (#3227)

*Issue #, if available:* CPFlows is a dependency for
`gluonts.torch.model.mqf2`, but it comes with dependencies constraints
that hold us back. So for example, not the latest numpy version was used
in CI tests.

*Description of changes:* Ignore dependencies of CPFlows in GitHub
workflows. Fix incompatibilities with the latest numpy.


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Backports v0.15.1 (reprise) (#3191)

*Description of changes:* backporting fixes
- #3188 
- #3189


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Co-authored-by: Oleksandr Shchur <[email protected]>

initial commit for v0.15.x

Backports for v0.14.4 (#3121)

*Description of changes:* backporting fixes
- #3094 
- #3115 

Additionally: cap pandas version to <2.2


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Co-authored-by: Jirka Borovec <[email protected]>

Backports v0.14.3 (#3077)

* Fix Rotbaum serialization and deserialization (#3068)

* Fix Rotbaum to handle short series (#3073)

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Co-authored-by: Anurag Pant <[email protected]>

Backports v0.13.9 (#3076)

* Fix Rotbaum serialization and deserialization (#3068)

* Fix Rotbaum to handle short series (#3073)

* fix after backport

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Co-authored-by: Anurag Pant <[email protected]>

Backports for v0.14.2 (#3063)

* Fix `iterable.Cached`. (#3060)

* Torch: Remove double caching of dataset. (#3061)

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Co-authored-by: Jasper <[email protected]>

Backports v0.14.1 (#3055)

* Refactor tests for `ev.aggregations` (#3038)

* Fix edge cases in metric computation (#3037)

* Add plt.show() to README (#3043)

* Rotbaum: Add item-id to forecast. (#3049)

* Fix mypy checks (#3052)

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Co-authored-by: Jasper <[email protected]>

Backports v0.13.8 (#3054)

* Refactor tests for `ev.aggregations` (#3038)

* Fix edge cases in metric computation (#3037)

* Rotbaum: Add item-id to forecast. (#3049)

* Fix mypy checks (#3052)

* add init

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Co-authored-by: Jasper <[email protected]>