Backport django4 branch changes to test factories
Backport django4 branch changes to test factories

For conflict free merges, changes in django4 branch effecting test
factories are backported (import changes).

volunteer-planner/volunteer_planner,christophmeissner/volunteer_planner,pitpalme/volunteer_planner,volunteer-planner/volunteer_planner,coders4help/volunteer_planner,volunteer-planner/volunteer_planner,christophmeissner/volunteer_planner,pitpalme/volunteer_planner,coders4help/volunteer_planner,christophmeissner/volunteer_planner,coders4help/volunteer_planner,pitpalme/volunteer_planner,pitpalme/volunteer_planner,christophmeissner/volunteer_planner,coders4help/volunteer_planner,volunteer-planner/volunteer_planner