Remove hostname param from govuk::host
Remove hostname param from govuk::host

We've never used this to make the hostname anything other than the resource
title. The title should always be the unqualified hostname of a machine. So
make it less confusing and error prone.

alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet,alphagov/govuk-puppet