[ENH] Add Working AutoETS algorithm

[alexbanwell1]

Reference Issues/PRs

Working implementation that supersedes #3032 and #3135
Resolves #3016 by fixing the bug at source

What does this implement/fix? Explain your changes.

Adds Working AutoETS algorithm

Does your contribution introduce a new dependency? If yes, which one?

No

Any other comments?

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I have added the following labels to this PR based on the title: [ enhancement ].
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[alexbanwell1]

Performance vs Statsforecast

[alexbanwell1]

Same graph as previously with the changes, approx same performance as statsforecast, but slightly slower:

[TonyBagnall]

I think we can probably optimise this, but other than the point about lags, it lgtm

[TonyBagnall]

small comment, but not a block at this point

[TonyBagnall]

LGTM now, nice