RFR: JDK-8207365: Make man pages optional

[Tim Bell]

Erik:
> The patch adds a configure parameter
> --enable-manpages/--disable-manpages, default is enabled, just like
> before the change. The patch also changes the Oracle configuration in
> jib-profiles.js to disable manpages.
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8207365
>
> Webrev: http://cr.openjdk.java.net/~erikj/8207365/webrev.01/index.html

Looks good.

Tim