Rewrite with new macros
Added some macros to simplify setup and try to ensure that people
actually do the obsoletes properly. They also will auto-generate the
summary so there's no need to do that manually.
This results in a single change to the list of obsoletes: the incorrect
obsolete of gnome-books <= 3.31.0 changes to < 3.31.0. This doesn't
appear to make any difference in practise.
It also fixes many missing items from the package list in the
description.