feat: add measure with unit

Author: metacosm

metadata/src/main/java/net/laprun/sustainability/power/Measure.java

@@ -0,0 +1,8 @@
+package net.laprun.sustainability.power;
+
+public record Measure(double value, SensorUnit unit) {
+    @Override
+    public String toString() {
+        return value + unit.toString();
+    }
+}