Instead of adding projects to the ServiceMeshMemberRoll object, it should be possible to add a project to a mesh by creating a ServiceMeshMember object in that project.

The original proposal provides more information about the reasons and benefits of introducing the ServiceMeshMember custom resource: https://docs.google.com/document/d/1S3jCGekYVAStqnQHAcNlMa63X7ma9TcKS9GA_o9yJ58/edit