refactor cdh plugin

CDH plugin can be refactored to make it easier for adding new version. I would like to do it as follow:
1. remove codes before CDH 5.5.0 (already done in https://review.openstack.org/#/c/444717/)
2. clean the code related CDH before 5.5.0. There are still some codes which include judgments statements about version like 5.4.0
3. the codes in version dir (like v5_x_0/"cloudera_utils.py", "config_helper.py", "db_helper.py", "deploy.py" and "validation.py"), most of these code are duplicated between each other. we can
 simply move them into base classes. If needed, we also can have a child dir like "cdh5" under "cdh" when "cdh6" releases in the future.
4. add cdh-5.10.0 support