Is your feature request related to a problem? Please describe.
From time to time (not regularly) I update my PMD configs. And then it is hard to find out what I have changed in my config and what you have changed.

Describe the solution you'd like
A commandline option to write the whole known rulesets including the default properties into a pmd-default.xml file.
This will allow me to have a simple diff between my configurations and your configuration with all its defaults.
This requires that you write out your configuration in a defined way, like first by programming language, then by section and then alphabetically. The properties should also written out alphabetically.
Also this might allow to automatically update the rules in a CI/CD context.

Describe alternatives you've considered
Verifying my config with your website rules section takes to much time and is too error prone!

Additional context
None