Clean/merge obsolete www docs

[marcparadise]

Assist releng team in merging chef.sh docs into the main doc site.
A PR is open: #1037

The intent is to update (in the PR above) the www/ docs

• merge orphaned content into existing pages
• add menu entries for orphaned content that should be present
• delete orphaned content that is no longer applicable.

To identify the orphaned content, deploy the docs locally (instructions in www/) and visit localhost:1313/. Anything identified as "Missing" needs to have one of the actions above applied.

Aha! Link: https://chef.aha.io/features/SH-687

[tyler-ball]

Closed by #1037