Refactored the base celery processing. Made everything resilient agains deadlock, segfaults, etc.

6 jobs for migration in 21 minutes and 39 seconds
Status Name Job ID Coverage
  Build
passed build #733558

00:12:55

passed buildgui #733559

00:01:01

 
  Test
passed linting #733560

00:01:37

passed tests #733561

00:06:05

84.0%
 
  Release
manual release #733562
allowed to fail manual
 
  Deploy
manual deploy #733563
allowed to fail manual