Integration Tests Code Coverage Support

This patch add the possibility to create Metrics for Integration Tests.
This method is a bit ugly... I know it's copy&pasted from JaCoCo: https://github.com/SonarSource/sonar-java/blob/8f65513f02cff2381360c0ba77d1055371042521/java-jacoco/src/main/java/org/sonar/plugins/jacoco/JaCoCoItSensor.java#L91

CoverageMeasuresBuilder doesn't handle Integration Tests out of the box

Would it be possible at least to use a Map<Metric, Metric> to map unit test coverage metrics to their corresponding IT metrics?