Support for 'license_scanning' - Update documentation

sub-issue for #8911 (closed)

Update documentation and mention deprecation of license_management naming, with support being dropped in the next major (13.0)

• https://docs.gitlab.com/ee/ci/yaml/README.html#artifactsreportslicense_management-ultimate
• https://docs.gitlab.com/ee/user/application_security/license_compliance/index.html#configuration