[yaml] Enhance YAML API docs

[Polber]

The current YAML API refernce docs look like the following:

This PR adds formatting to make the docs look more like the Sphinx-themed PyDocs used by the Python SDK:

This change not only adds some color and easier-to-read formatting, but also separates the transforms into individual pages to reduce clutter. This should hopefully make the user-experience a bit better.

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[Polber]

R: @robertwb

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