Utilities/Release: Add script to consolidate release notes

Utilities/Release/consolidate-relnotes.bash

+#!/usr/bin/env bash
+
+set -e
+
+usage='usage: consolidate-relnotes.bash <new-release-version> <prev-release-version>'
+
+die() {
+    echo "$@" 1>&2; exit 1
+}
+
+test "$#" = 2 || die "$usage"
+
+files="$(ls Help/release/dev/* | grep -v Help/release/dev/0-sample-topic.rst)"
+title="CMake $1 Release Notes"
+underline="$(echo "$title" | sed 's/./*/g')"
+echo "$title
+$underline
+
+.. only:: html
+
+  .. contents::
+
+Changes made since CMake $2 include the following." > Help/release/"$1".rst
+tail -q -n +3 $files >> Help/release/"$1".rst
+sed -i "/^   $2 / i\\
+   $1 <$1>" Help/release/index.rst
+rm $files