Minor documentation reorganization

[Russ Allbery]

I'd like to start moving more of INN's text documentation into the doc
directory instead of being scattered around the tree, with the long-term
parallel goal of creating a $prefix/doc (or $prefix/share/doc if FHS is
turned on) directory and installing all those bits into it.  It will also
unclutter the top directory a little.

Anyone object if I move the README.*hook files into doc, calling them
something like doc/hook-perl, doc/hook-python, etc. and updating the
pointers in the other documentation?

-- 
Russ Allbery (rra at stanford.edu)             <http://www.eyrie.org/~eagle/>