These files have been in the distribution for some time but haven't been
installed. They are good examples of how to do things, so we should
install them.
Since deptree2dot and the perl requirement are completely optional, we
can move this tool to the support folder. This gives the user the option
of using it if they have perl installed, and means we do not have an
optional runtime dependency on perl.
Documentation for this tool has also been added to the support folder.
X-Gentoo-Bug: 600742
X-Gentoo-Bug-URL: https://bugs.gentoo.org/show_bug.cgi?id=600742
