Split Docs into Unittest- and Pytest-style Pages

[shawnbrown]

Seeing the entire API on a single page can create confusion when users aren't familiar with the differences between unittest and pytest style conventions. It's not always apparent which method or function format is appropriate and mixing these different conventions is not advisable.

The API Reference page should be split into two sections:

• Unittest-style Syntax
• Pytest-style Syntax

[shawnbrown]

This was addressed with the sphinx_tabs plugin starting in March, 2018:

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