Add GDS Verify module changes

GDS Verify(IDA) project use a fork of this graphite module. It seems like a good idea to incorporate changes in to this module, with the view the Verify project dropping the fork and using only this module.

The GDS Verify additional changes are:
 - Ability to specify the user used to run the processes
 - Install from Debian package
 - Some carbon cache options
Hence it would be good in the commit to explain why the normal service restart has been disabled, because by disabling [`hasrestart`](https://docs.puppetlabs.com/references/latest/type.html#service-attribute-hasrestart) and not supplying an alternative [`restart`](https://docs.puppetlabs.com/references/latest/type.html#service-attribute-restart), Puppet will do a `stop` followed by a `start`.