[MNT, ENH, DOC] Rework similarity search

[baraline]

Reference Issues/PRs

Fixes #2341, #2236, #2028, #2020, #1806

What does this implement/fix? Explain your changes.

The previous structure for similarity search was not in line with the structure we would expect considering other aeon modules, the lack of distinct base classes for some tasks, as well as the initial design choice (due to the lack of practical experience with using and expanding the module) lead to some really complex code when working on #2341 to make everything work together. Further expanding the module would have made thing worse.

To make the module more flexible and comprehensible, the following rework is proposed in this PR (AEP to be updated acordingly):

• Focus the module on two distinct tasks : find_neighbors and find_motifs for all type for similarity search estimators
• Distinguish between two kind of similarity search tasks with the two submodules, SeriesSearch and SubsequencesSearch. The SubsequencesSearch focuses on tasks for which the goal is to find motifs or neighbors in subsequences of time series (e.g. Matrix Profiles, Motiflets, etc.). the SeriesSearch focuses on task using whole series (e.g. Indexes such as LSH, iSAX, etc.)
• Keep the flexibility of the k, threshold and inverse_distance parameters to customise search outputs
• Have base classes for families of method to limit code duplication (e.g. BaseMatrixProfile, and STOMP, where most existing code was ported)

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

No.

Any other comments?

As this is still a WIP, I would love some inputs on the structure (notably from @patrickzib !) to make the module more future-proof to future additions and easier to use.

TODO list :

• Finish to include testing suite for base estimators in the testing module for the SubsequenceSearch part
• Implement LSH index as a simple first case for BaseIndexSearch
• Implement tests for SeriesSearch base class and estimators
• Update API docs / doc pages
• Update notebooks
• updated aeon's CODEOWNERS to receive notifications about future changes to these files.

[aeon-actions-bot]

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I have added the following labels to this PR based on the title: [ $\color{#F3B9F8}{\textsf{documentation}}$, $\color{#FEF1BE}{\textsf{enhancement}}$, $\color{#EC843A}{\textsf{maintenance}}$ ].
I have added the following labels to this PR based on the changes made: [ $\color{#006b75}{\textsf{similarity search}}$ ]. Feel free to change these if they do not properly represent the PR.

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