Add files and archives tags to workflows

The <files> and <archives> tags in Oozie allow worflows to use files in hdfs through the distributed cache. For long running clusters, exposing these tags in Savanna will allow reuse of libraries stored in hdfs and in some cases will eliminate the need to bundle files with individual jobs.

For ephemeral clusters this is not as useful, since files would have to be uploaded to hdfs on the fly anyway. In the case of ephemeral clusters the /lib directory is probably adequate for bundling extra files.