Time serie selection handled by the advanced metadata panel

[mattiagiupponi]

The time selection is going to be added to the advanced metadata page in the settings panel. If the has_time is selected a new panel for the time series settings is open: In the attribute and end_attribute fields, only the xsd:dateTime fields are displayed. Based on the selection of the presentation, two new input boxes are loaded to let the user configure the time series: The ? open a modal with some information about "how to configure" the time series Internally the dataset_metadata view will communicate with GeoServer to configure the time series. If the has_time is removed, also the configuration in GeoServer is disabled.