Aerial multi l2

This MR makes the name of the shared memory that is used to communicate between OAI VNF and NVIDIA PNF configurable. This allows that one instance of L1 can be used with multiple instances of L2. See https://developer.nvidia.com/docs/gputelecom/aerial-sdk/text/cubb_quickstart/running_cubb-end-to-end.html#run-multiple-l2-instances-with-single-l1-instance for more info. This MR also includes the possibility to pin the NVIPC thread to a specific core. It also removes the unused P7 thread.