MINOR: cpu-topo: add a new "efficiency" cpu-policy

MINOR: cpu-topo: add a new "efficiency" cpu-policy

This cpu policy tries to evict performant core clusters and only
focuses on efficiency-oriented ones. On an intel i9-14900k, we can
get 525k rps using 8 performance cores, versus 405k when using all
24 efficiency cores. In some cases the power savings might be more
desirable (e.g. scalability tests on a developer's laptop), or the
performance cores might be better suited for another component
(application or security component).