Fix errors on infra page, build ordered lists

The changes recently merged to the infrastructure page did not
completely incorporate the edits from the technical writer. The (long)
example YAML file was included twice, and the numbered list
restarted at 1 in a few places because of code blocks that weren't
fully indented.

This MR adds in consistent line breaks to the page, rewrites several
tiny subheadings to be a single list of numbered steps, and fixes
the problem with the doubled copy of the code example.