Python Style Guide PEP 8 Refactor

I’ve been implementing research by @timj, @parejkoj and @frossie (during a SQuaRE Hack Day) on how our existing Python Style Guide can be rephrased as a diff against PEP 8. This work takes the perspective that Python programmers already share a universal style guide (PEP 8) and that DM’s style guide should only express tweaks and additions to that guidance.

Since the style guide is an important resource for all DM developers, I encourage you to follow the PR thread: https://github.com/lsst-dm/dm_dev_guide/pull/56

Feel free to let me know in the PR what can be clarified and to point out any typos or inconcistencies that exist so far.

I’ve also suggested a general section re-organization in that PR thread. Let me know what you think.

Keep in mind that the scope of the work is limited to implementing currently-accepted RFCs and we can’t change the intent of the Python Style Guide. And of course, @ktl has the final word when this PR ultimately goes into review.