Add netcfgbu and fix MD linting

[petercrocker]

Explanation

I added line 423, netcfgbu, written by Jeremy Schulman and I knew a few of my customers using it.

The rest of the changes are all simple markdown linting fixes. Spaces where they shouldn't be. Mixed levels of indent spacing when it should be consistent. If we want awesome automation, we should make sure our code passes the linter in the CI pipeline 😊

If you want me to resubmit without the linting, no worries, let me know!