Add core config

[renestalder]

Add a core config to util which is loaded in any case with default configs. This solves the problem of missing configuration parameters on updates if the developer doesn't replace the development and production configs.

This enables to overwrite the util and tasks folders as long the developer only changes configs in the gulp folder. After overwrite, alls tasks still work and new tasks can grab their configs from the core configuration. This enables the developer then to add configurations of newly added tasks to his config.