Update old links in README.md, CONTRIBUTING.md, NOTICE.md
In the README.md, CONTRIBUTING.md and NOTICE.md in the opSimulation repo (https://gitlab.eclipse.org/eclipse/openpass/opSimulation) almost all links (incl. link to the new dev mailing list) are not updated yet.
Additionally, check the links in other sub-repositories.
//CC @tplatzer
issue