Blueprints reuse existing configuration

The 'website' and 'mobile' blueprints are currently reusing the existing HST configurations 'gogreen' and 'mobile'. As a result, all newly created channel point to the same configuration. Editing the configuration of new channels will therefore also modify the configuration of all these other channels, which is underirable.

Instead, each blueprint should contain an hst:configuration node with the blueprint HST configuration of that channel.