Add Patches/<package>/Patches/README.rst files

Add a README.rst to each package Patches directory to document its
purpose and reference the top-level README.rst file.  This will aid
users that arrive in a repository browser through a link pointing
directly at a Patches directory for a package.

Use the following shell code to create the files from Packages.csv:

cd Packages &&
tail -n +2 ../Packages.csv |
egrep '^[^,]+' |
while IFS=, read pkg dir _; do
  mkdir -p "$dir/Patches" &&
  hdr="$pkg Patches"
  line="$(echo "$hdr"|sed 's/./=/g')" &&
  echo >"$dir/Patches/README.rst" \
"$line
$hdr
$line"'

This directory holds VistA patches for the package::

  '"$pkg"'

Each immediate subdirectory is named after one VistA patch and
contains host files for the patch.

See `<../../../README.rst>`__ for details.'
done &&
cd ..

Change-Id: Id69d2fce73a1b34c3e50cca99585bb252b356528