CDK-668: Update maven plugin to setup DefaultConfiguration.

Previously, properties set in the plugin's configuration were local and
the getDatasetRepository method had to use repository builders to use
the correct file system. This updates the method to create repository
URIs instead and changes the getConf method to update the default
Configuration.
To add to this. This means that the Dataset URI would be `dataset:hive:ns/dataset?location=/path/to/dataset` but the DatasetRepository URI is `repo:hive:/path/to/`, is that right? That is confusing.