migrated example: Custom Tasklist Exporter based

[jonathanlukas]

Description

This example has been migrated

Additional context

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
• I have added a build job for my example to .github/workflows/build.yaml