Add modernizer-maven-plugin to build

This plugin finds use of legacy APIs:

https://github.com/andrewgaul/modernizer-maven-plugin
This is causing the build to fail. This parent pom depends on jclouds-resources, and vice-versa, so the first build will fail (and this is the cause of the Jenkins failure).

To prevent this, there are the "jclouds-project" and "not-jclouds-project" profiles. Those are used for example to configure the checkstyle plugin to get the config file from the classpath or from the filesystem: when building the main jclouds repo you need to use a filesystem path and don't add the jclouds-resources dependency to the plugin (because the dependency may not yet exist), and when building downstream projects, the config file must be read from the classpath and the dependency must be added to the plugin config.

Could you add the modernizer plugin to those profiles and use a similar configuration?