Added additional functionality and cleaned up a lot of extra stuff.

Few changes:
* Removed the cassandra and mongo scripts, as they were unused and somewhat unnecessary.
* Added configuration steps beyond what was previously available. These steps include preparation (zncrypt-prepare), encryption (zncrypt-move), and addition of ACL's (zncrypt acl --add). Also added support for multiple encryption targets and ACL binary targets.
* Added more intelligent checking, allowing to rerun scripts multiple times without issue/error.
* Minor updates and changes.