Improve icephys tutorial

[h-mayorquin]

Motivation

At the moment, the icephys tutorial begins with a very general overview, presented in the style of a reference manual: it includes a summary graph, a list and description of all data types, and a complete code example with all use cases.

I believe the tutorial would be more effective if it progressed from the simplest case to the most complex. This PR reorganizes the tutorial accordingly:

• Start with adding a single Stimulus and Response Series.
• Then, explain how to organize multiple experiments using intracellular recordings.
• Finally, introduce the Simultaneous, Sequential, Repetition, and ExperimentalConditions tables as tools for organizing more complex experiments.

This PR establishes the general structure, but there are still some improvements we could consider:

• Provide a clearer description of the metadata associated with Electrodes and PatchClampSeries, that is, the optional arguments.
• Add diagrams illustrating experimental setups where the various tables (Simultaneous, Sequential, Repetition, and ExperimentalConditions) are used.

However, I think these enhancements can be added later.

Checklist

• Did you update CHANGELOG.md with your changes?
• Have you checked our Contributing document?
• Have you ensured the PR clearly describes the problem and the solution?
• Is your contribution compliant with our coding style? This can be checked running ruff check . && codespell from the source directory.
• Have you checked to ensure that there aren't other open Pull Requests for the same change?
• Have you included the relevant issue number using "Fix #XXX" notation where XXX is the issue number? By including "Fix #XXX" you allow GitHub to close issue #XXX when the PR is merged.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 94.83%. Comparing base (b331e9c) to head (239131b).

Additional details and impacted files

@@           Coverage Diff           @@
##              dev    #2071   +/-   ##
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  Coverage   94.83%   94.83%           
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  Files          28       28           
  Lines        2749     2749           
  Branches      708      708           
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  Hits         2607     2607           
  Misses         82       82           
  Partials       60       60           

Flag	Coverage Δ
integration	73.99% <ø> (ø)
unit	84.83% <ø> (ø)

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