doc: move topics/guides to website

This commit removes the topics and guides that the documentation
working group has proposed added to the website. We want them to have
more visibility and believe that moving them to the website does that.

Ref: nodejs/nodejs.org#1105
Fixes: nodejs#10792
PR-URL: nodejs#10896
Reviewed-By: Gibson Fahnestock <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Sakthipriyan Vairamani <[email protected]>
Reviewed-By: Colin Ihrig <[email protected]>
Reviewed-By: Stephen Belanger <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Sam Roberts <[email protected]>

Author: evanlucas