[BPMN] Reuse Data Types across the process - Community Documentation

Documentation:

• Include some release notes for this new feature in the community documentation
• Check existing community documentation and figure out if some section needs update

Links

Community doc -> https://docs.jboss.org/jbpm/release/7.44.0.Final/jbpm-docs/html_single/#jbpmreleasenotes

Community documentation repo -> https://github.com/kiegroup/kie-docs