Adjust payment example for Camunda 8.8

[ingorichtsmeier]

Description

Renovate the example application to the latest Camunda 8.8 features

Additional context

Having tagged images of the application with different versions of Camunda helps to simulate migration scenarios.

It is not always the case, that the cluster version fits the process application versions, as they are loosely coupled

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