Automatically create canonical dataset views

[deniszgonjanin]

When a new resource view is created, if the dataset to which it belongs to does not have a canonical view, one should be created from the new resource view.

A setting would be nice to specify which resource view types should be automatically created into canonical views, like so:

ckan.featured.default_views = recline_grid_view geojson_view ...

This might be a bit difficult to implement - need to find a way to listen to the creation of new resource view objects.