perl5 Initial commit for Notebook-Util package

- included documentation for building and installing perl modules in
  README
- Notebook-Util uses Dist::Zilla as build tool
- so far only Notebook::Util::Command is included
perl5: Added Notebook::Notify to repo

- new config file ~/.config/notebook-setup.ini
share: added icons used with Notebook::Notify
perl5 added screen-brightness script to Notebook-Util paket

- adapted path in fvwm config as well