This listens to when configuration is being initialized and sets our own

defaults, helping to enforce a consistent style across our documentation

and to reduce the work needed to set things up.
The defaults turn off the Numpy and Google docstring parsers, set

standard autodoc class ordering and flags, and ensure our own type

hinting is used.
It sets some autodoc defaults that we end up setting in each codebase,

and normalizes autodoc_excludes.
If a codebase needs to, it can opt out of these defaults by setting

use_beanbag_autodoc_defaults=False.
It registers unicode as a type that maps to str when building

against a Python 3 intersphinx or against the unicode function when

building against a Python 2 intersphinx.
And finally, it returns version information for the extension so that

any new versions will cause a doc rebuild.

Unit tests pass.
Tested these with a couple codebases, and the default options removed

from the codebase's conf.py. Didn't see any regressions.