Note: inspired by CCC talk https://media.ccc.de/v/35c3-9788-memsad
It'll be probably removed after we see what portion of packages
this affects.

This reverts commit 91010ef4.

Helped-by: Karel Koci <karel.koci@nic.cz>

Helped-by: Karel Koci <karel.koci@nic.cz>

This reverts commit d38d7a1e.

We foundout why these weird dependencies are there. That is because
dependencies are resolved for whole package not just for specified build
package. This results to build of all python versions even if only one
of them in reality is needed. These dependencies mask that and ensure
that if package is going to be build that its python version is skipped.

This reverts commit 5d175ac8.

Userlists are now named as pkglists and are required bu
updater-ng-supervisor so no problem with drop there.