doc: clarify rules regarding corporate contributions #12542
Description
Witness the confusion in issue #12452 (Oracle not being listed in AUTHORS).
The contributing documentation should clarify more about how to submit corporate-owned code. (e.g. using your corporate email address in Gerrit, or if a mix of personally- and corp-owned code, making sure first that the corporate name is in the AUTHORS file first, and specifying the copyright holder per commit?).