Setup for adding JavaType marker after parsing XML

[Laurens-W]

What's your motivation?

• Add trait to identify java package references in xml #4587 (comment)

Anything in particular you'd like reviewers to focus on?

Anyone you would like to review specifically?

@knutwannheden @timtebeek

Have you considered any alternatives or workarounds?

• Add trait to identify java package references in xml #4587

Any additional context

Checklist

• I've added unit tests to cover both positive and negative cases
• I've read and applied the recipe conventions and best practices
• I've used the IntelliJ IDEA auto-formatter on affected files

[knutwannheden]

I think we should probably move this marker to rewrite-core and name it something like TypeReference and then possibly add a language property to it. This way FindType, ChangeType and other recipes can support it and can at the same time be independent of the language that the markers occur in.