Walkthrough example cleanup
Walkthrough example cleanup

- Add kubectl command examples
- Add tables of contents
- Skip 3rd header tier to make sections more clear
- Reference cmd-exec example for curling pod & service IPs
- Make section layout, text patterns, changes & links more consistent
- Canonical yaml formatting

kubernetes/examples,kubernetes/examples,kubernetes/examples,kubernetes/examples,kubernetes/examples,kubernetes/examples,kubernetes/examples,kubernetes/examples