Merge pull request #1 from aodn/ui-extension-experimentation

UI For Configuring Layer Filters in GeoServer
Return to the layer listing page for filters when cancelling a layer's
filter form
Merge pull request #3 from aodn/form-cancel-button-behaviour

Return to the layer listing page for filters when cancelling a layer's filter form
Merge branch 'master' into ows-filters-service
Use helper method to get the file path