Add support for energy perf policy (it needs kernel module msr and program x86_energy_perf_policy from linux-tools)

Signed-off-by: Thomas Koch <linrunner@gmx.net>
x86 energy perf policy:
 * Rename params to ENERGY_PERF_POLICY_ON_BAT/AC
 * André's suggestions
 * DEB: recommends linux-tools
 * README, changelog