RFR: JDK-8180178 Restructure existing man pages according to JEP 299

[Magnus Ihse Bursie]

In preparation for JDK-8178317, the existing man page troff sources will 
be moved to their corresponding modules, according to the layout 
determined by JEP 299. During the docs build, they will be copied to the 
man directory in the docs image, as specified by JEP 299. No markdown 
conversion will be done for now, though.

Note that this will only apply to OpenJDK, not the Oracle JDK, which do 
not ship the man pages from the OpenJDK repository. (This has not been 
the case since at least JDK 8.) Also note that the man pages themselves 
have not been updated. I did update "JDK 8" to "JDK 9", but I have made 
no other changes. Nevertheless, I believe having man pages (even if 
outdated) is better for the community than not having man pages.

The jhat and jsadebug tools have been removed in JDK 9, so I removed 
these man pages as well.

Prior to this reorganisation, the man pages were duplicated in three 
directories, one for each of solaris, linux and bsd. I have verified 
that for the remaining man pages, there were no substantial difference 
between these versions.

Bug: https://bugs.openjdk.java.net/browse/JDK-8180178
WebRev: 
http://cr.openjdk.java.net/~ihse/JDK-8180178-restructure-man-pages/webrev.01

/Magnus