Improve logging of complete user tasks scripts.

[ingorichtsmeier]

Description

Improve the logging output of the cronjob and script to complete user tasks.

Additional context

Remove the single run Kubernetes job to complete user tasks. It can be created from the cronjob. The command is documented in the README.

This pull request should be merged before the switch to 8.8 in #909.

Types of changes

• Bug fix (non-breaking change which fixes an existing open issue)
• New example (non-breaking change which adds functionality to an extension)
• Documentation update (changes made to an existing piece of documentation)

Checklist:

• My code is formatted by spotless
• I have added at least one meaningful test to assert the behaviour of the example.
• I have created documentation that informs about the purpose, the functionality and how to setup the example

[ingorichtsmeier]

Hi @jonathanlukas, I did some small improvements. Could please check and merge again?

Thank you!

I will continue with 8.8 then.