add template-based report tool #72

let's split reporting in two parts. this issue is about template-based reporting.
while bauble and ghini.desktop users have been struggling to get that stiff pdf report tool going, people have been solving the issues in very many other ways.
https://www.reportbro.com/demos/deliveryslip
https://github.com/auto-mat/smmapdfs
https://django-easy-pdf.readthedocs.io/en/v0.2.0-dev1/usage.html