Re-implement Calmness in Java

[atpoverload]

Adapt the calmness logic from https://github.com/pl-chappie/chappie/blob/master/fse2020/analysis/freq-calmness.py to Java. We want to be able to do something like this:

// do something
List<CpuFrequency> trace1 = jcarbon.getSignal(CpuFrequency.class);
List<Double[]> utilization1 = toUtilization(trace1);
// do something else
List<CpuFrequency> trace2 = jcarbon.getSignal(CpuFrequency.class);
List<Double[]> utilization2 = toUtilization(trace2);
UtilizationSimilarity similarity = correlate(utilization1, utilization2);
System.out.println(String.format("spatial:%.6f, temporal:%.6f", similarity.spatial, similarity.temporal));