Skip integration tests when using one of the Maven dedicated options

That should natively work with WebDriver tests since they are based on maven-failsafe-plugin.
That need to be done on nuxeo-distribution-tools to make it work with Selenium, Funkload and avoid useless server start/stop.

Like Unit test, Integration tests should be run by default.
So -DskipITs, -DskipTests and -Dmaven.test.skip=true must be taken in account by nuxeo-distribution-tools, tools-nuxeo-ftests, or its configuration in the corresponding POMs.