[ENH] Tidy, deprecation actions and testing for sklearn estimators

[MatthewMiddlehurst]

What does this implement/fix? Explain your changes.

• Adds ClassifierMixin and RegressorMixin to sklearn estimators
• Carries out some deprecation actions for the classifier
• Adds sklearn testing for regressor rotf
• Makes some changes to data processing to accommodate for the above

[aeon-actions-bot]

Thank you for contributing to aeon

I have added the following labels to this PR based on the title: [ $\color{#FEF1BE}{\textsf{enhancement}}$ ].
I have added the following labels to this PR based on the changes made: [ $\color{#BCAE15}{\textsf{classification}}$, $\color{#7E0206}{\textsf{regression}}$ ]. Feel free to change these if they do not properly represent the PR.

The Checks tab will show the status of our automated tests. You can click on individual test runs in the tab or "Details" in the panel below to see more information if there is a failure.

If our pre-commit code quality check fails, any trivial fixes will automatically be pushed to your PR unless it is a draft.

Don't hesitate to ask questions on the aeon Slack channel if you have any.

PR CI actions

These checkboxes will add labels to enable/disable CI functionality for this PR. This may not take effect immediately, and a new commit may be required to run the new configuration.

• Run pre-commit checks for all files
• Run all pytest tests and configurations
• Run all notebook example tests
• Run numba-disabled codecov tests
• Stop automatic pre-commit fixes (always disabled for drafts)

[TonyBagnall]

if not already there, could you add the deprecation actions to this list and tag it? Sorry, I like lists :)

#1393

[TonyBagnall]

lgtm