[MRM-265] - added method for deleting the artifacts in the db when a repo is deleted - also deleted repo scan statistics when the repo is deleted - created DAO that does retrieving, deleting and adding of RepositoryContentStatistics to the db - added and updated tests
maven/archiva/trunk/archiva-base/archiva-consumers/archiva-database-consumers/src/main/java/org/apache/maven/archiva/consumers/database/ProjectModelToDatabaseConsumer.java