Document that you can use sudo at the task level as well

Link people right to this page on Github, so they can click "edit" right there. No need for them to search for the repo, figure out that the docsite isn't a separate repo, and navigate to the given dir.

The Roles section assumes some familiarity with vars_files, which this note attempts to briefly provide.

Showcase the new-style lookup plugin access in the authorized_key docs rather than the old-style $FILE

Showcase the new-style lookup plugin access in the authorized_key docs rather than the old-style $FILE

Explain conditionals as applied to roles.  I could also explain with_items but the scope questions are complex
here, and it is better to include such loops inside the imported tasks.