Investigate packages used for yaml marshalling

WHAT
During the work to implement the importas linter I came across three different packages being used to marshal yaml. I would suspect only one is need.

This ticket is about investigating why the different packages are used and deciding if any thing can be done to reduce the number of the different uses.

HOW
<Suggestions for how this may be solved. [Optional]

TESTS
<List of related tests>

DONE

• understanding of why there is three different yaml packages in use.