Add CPack instructions for deb releases

This MR adds the required instructions for CPack to create a proper Debian package. Current artefact created with this: mmmtools_0.1.0.deb

How to Reproduce

Save this script as make-deb-package.sh in the MMMTools project root folder:

#!/bin/bash

set -e

mmmb="$(pwd)/build"

echo "MMMTools build directory is $mmmb"

ldlp="$LD_LIBRARY_PATH:$mmmb/lib"
ldlp="$ldlp:$mmmb/imuConverterPluginLibs"
ldlp="$ldlp:$mmmb/motionConverterPluginLibs"
ldlp="$ldlp:$mmmb/motionHandlerPluginLibs"
ldlp="$ldlp:$mmmb/segmentationPluginLibs"
ldlp="$ldlp:$mmmb/sensorVisualisationPluginLibs"

echo "LD_LIBRARY_PATH is now $ldlp"

(cd build && cmake .. && LD_LIBRARY_PATH="$ldlp" make package)

Run bash make-deb-package.sh from within the MMMTools project root folder.