Rewrite scheduling in mapswipe_workers.py

[Matthias-Schaub]

The setup of the scheduler in mapswipe_workers is done repeatedly. This takes up a lot of space and makes it less readable. Furthermore this introduces a weird phenomena where the click function/command (e.g. run_create_projects()) will only handle scheduling and passing to the scheduler another function (e.g. _run_create_projects()) which implements the desired functionality. This is confusion. There should not be two functions with almost the same name.

A solution could be adding a scheduling handler which will be called by the click function/command (e.g. run_create_projects).

[Matthias-Schaub]

This issue has been adressed in merge "Rewrite of the cli mapswipe_workers.py. #265"