`ima_v2` should match the convention introduced by the cookiecutter template.

Changes introduced to `ima.py` are to allow execution in cluster mode. After some experiment with replacing hive with `spark-sql` shell, I rolled back to using Hive for IMAv1. Some semantics difference make the final export fail. We should consider dropping anyway, since it breaks convention (data should be stored on HDFS/Swift instead). IMAv2 does use `spark-sql` under the hood.