Maven multi module: no need to copy paste xmlReportPaths property

[Sam-Kruglov]

The following works for my case:

<!--suppress UnresolvedMavenProperty - for IDEA -->
<sonar.coverage.jacoco.xmlReportPaths>
    ${maven.multiModuleProjectDirectory}/aggregator-project/target/site/jacoco-aggregate/jacoco.xml
</sonar.coverage.jacoco.xmlReportPaths>

This needs to be defined in the parent project only