Formalize the Dioptra Client

[alexb1200]

Towards Resolving #210

• document the dioptra client class
• move to dioptra.client namespace
• began refactors of examples, pending PR examples: merge and update imagenet resnet50 examples (pt & fgm) #215 and Update Example: ahand-pytorch-mnist-mi #202

[jkglasbrenner]

Preparing to review: I split off the changes under the examples/ folder to another branch, https://github.com/usnistgov/dioptra/tree/examples-use-moved-dioptra-client. I am also squashing and rebasing the rest of the commits on the dev branch to make sure all of the tests continue to pass.

[jkglasbrenner]

Most of this review is focused on the whitespace structure of the docstrings themselves. Basically, although there are 64 comments, a lot of them are duplicative and are just there to flag the places I noticed something to be addressed.

The change requests are mainly about how to update the docstrings so they conform with the 88 characters or less per line style rule and ensuring there are 4 spaces per indentation level. There's also suggestions on how to structure the whitespace for the responses in the example blocks so they're following a consistent style everywhere. The rest are just minor things like deleting extra lines of whitespace.