Adding support for HLT virtual seeds (polymer, new sso)
This MR merges in support for HLT virtual seeds on top of the polymer version with the new sso.
It superseeds !206 (closed)
It is currently deployed at https://kvm-s3562-1-ip149-30.cms and seems to work as expected (although should test a L1-HLT mismatch just to be sure)