Added ability to include clustername in usernames

This release deals with some users desires to include the clustername as part of the service account names. This is particularly useful in some cases where a singular KDC is used but one wishes to impart unique users between tenants. More on this can be found here: https://community.emc.com/community/products/isilon/blog/2016/04/26/ambari-automated-kerberos-configuration-with-emc-isilon

As well the updated scripts change the previous behavior of using isi_run in favor of chmod and chown. This drastically reduces run-time on busy systems. -Thank you sile16

In the next release we will return a list of users and groups created by this script that can be used to pre-populate Linux hosts with matching users/UID's/GID's. While it is not a requirement with the HDFS specification that UID/GID match for the service accounts, it does matter that user/UID/GID match for user accounts that wish to make use of other protocols about the same data as HDFS. Because of this it makes sense that service accounts also match for the sake of consistency.

The next release will also retire the original PHD users and groups. (PHD < 3.x)