enable geonode to filter feature attributes by Url Parameters through the cql_filter

[ffischer1984]

the geonode already provides an embbed-url to embbed datasets in other web-applications (.e.g. as an iframe) but currently there is one disadvantage.
It's only possible to display the whole dataset - it's not possible to filter a geometry/feature by url paramter filter-attributes this limits the possibilites for consumer-webapplications.