Documentation for: BarkerSampling(), AGPJL() and ObservationSeries

[odunbar]

Purpose

Closes some docs gaps from recent work:

• Closes Add docs API and documentation in the use of Observations etc. from EKP #385
• Closes some docs items in O6.2 Create SOTA gradient-based Samplers #340
• Closes Docs: Add the encoding schedule in the docs for example #382
• General docs clean

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Content

• Added ObservationSeries/Observations notes
• Added AGPJL section and the current interface for training
• Added notes on differentiable BarkerSampling and protocols for autodifferentiable packages
• Added general improvements to the posterior distribution as (Chain/ParameterDistribution/Dict/Array) and how to reduce to the desired (un)wrapping
• Updated runs for Sinusoid, including new text, appropriate prior, and new figures from latest CES and data processing
• Update figures for GFunction and L63 emulator examples with latest CES and data processing
• Updated other example snippets to include the correct data processing as in the examples.
• Add some quick links to index and readme!

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• I have read and checked the items on the review checklist.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.18%. Comparing base (2d80bc9) to head (09eb2cf).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

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  Coverage   94.18%   94.18%           
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  Files          10       10           
  Lines        1807     1807           
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  Hits         1702     1702           
  Misses        105      105           

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[odunbar]

As this just updates docs, will merge on tests passing and docs build correctly