Add a Null instance of the TlsLib class. This lib instance
can be used as a template for new implementations of the TlsLib
class and can also be used to reduce CI build times for build
checks that depend on the TlsLib class.
Cc: Jian J Wang <jian.j.wang@intel.com> Cc: Xiaoyu Lu <xiaoyux.lu@intel.com> Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com> Reviewed-by: Jian J Wang <jian.j.wang@intel.com>