Commonhaus's IP policy requires reference to the DCO in CONTRIBUTING.md

https://github.com/commonhaus/foundation/blob/main/policies/ip-policy.md

Somewhere I've also see a request for "Compliance with Laws and Regulations" language, although I'm not finding the reference.

Basically I think we should port the https://github.com/commonhaus/foundation/blob/main/CONTRIBUTING.md 'Legal' section to wildfly/wildfly-core CONTRIBUTING.md, except mentioning ASL.