feat: readme update for xml record builder

[Joel-hanson]

Description

Update readme with information on how to use the XmlMQRecordBuilder

Type of change

• This change requires a documentation update

How Has This Been Tested?

Tested it with unit tests

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[dalelane]

Note that we should change the commit message to start with docs: instead of feat: (as "feat" indicates a commit that introduces a new feature) but we can fix that on merge

[dalelane]

what is "connectorConfigProps"?

Why wouldn't you configure it through normal connector config?