Get rid of all our embedded copies of Module::Install

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Really support building Perl modules from a separate builddir

Signed-off-by: Anders Kaseorg <andersk@mit.edu>
Module::Install::BarnOwl: Create .par files with Module::Install::PAR

Signed-off-by: Anders Kaseorg <andersk@mit.edu>