Avoid decomposition of Publish fields into method params

[andsel]

Release notes

Refactory of PostOffice to pass publish message in hits entirety avoiding decomposition into single parameters.

What does this PR do?

Updated all PostOffice methods that accepted QoS, topic, retained flag and payload, components of a publish message to move around just the publish message without decomposing it.

Why is it important/What is the impact to the user?

As developer I want to have the smallest and cohesive parameters list passed around method calls.

Checklist

• My code follows the style guidelines of this project
• I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [ ] I have made corresponding change to the default configuration files (and/or docker env variables)
• [ ] I have added tests that prove my fix is effective or that my feature works
• I have updated the Changelog if it's a feature or a fix that has to be reported

Author's Checklist

• [ ]

How to test this PR locally

Related issues

• Relates Payload format and content type #825 Payload format verification and content type properties handling #826

Use cases