Add rocky8 and omega pipelines
Add support for rocky8 and omega in the OSDU build rules.
rocky8 binaries can be used for distros based on Red Hat 8 or CentOS 8.
omega is a special version of rocky8 where the c++ ABI uses the old definitions (pre-c++11) for std::string. This allows linking with legacy libraries that cannot be rebuilt. Google _GLIBCXX_USE_CXX11_ABI for details.