doc: add links to alternative versions of doc

Each page of the API documentation should have links to other versions
of the same page. This will make it easier to switch between the current
"live" release at nodejs.org and LTS versions.

PR-URL: https://github.com/nodejs/node/pull/10958
Fixes: https://github.com/nodejs/node/issues/10726


Reviewed-By: Refael Ackermann <refack@gmail.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>
Reviewed-By: Sakthipriyan Vairamani <thechargingvolcano@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>