Extend the plugin descriptor processing to also configure releases information for repositories

Essentials plugin descriptors can have configuration to add an extra repository definition to a pom.xml file. A releases section for such a repository section cannot be added though. Add this option, so the json snippet below will be handled correctly. The class org.onehippo.cms7.essentials.dashboard.model.RepositoryRestful should be updated to provide this.

"repositories": [
{
"@type": "repository",
"id": "hippo-maven2-enterprise",
"name": "Hippo Enterprise Maven 2",
"url": "https://maven.onehippo.com/maven2-enterprise",
"targetPom": "project",
"releases":

{ "@type": "releases", "updatePolicy": "never", "checksumPolicy": "fail" }

}
]