TextList list-filter widget should handle multiple-value criterias

[Pictor13]

At the moment the widget just splits the incoming value(s) by delimiter (comma), leading multiple values for criterias like range or spatial to not be parsed correctly.

E.g. value range(gte:10082,lte:16835) will be wrongly split into two values

Filter value should be split according to the regex defined in FilterCriteria, and rebuild the value correctly for submit if needed.
In alternative the value should stay unaltered, as a single criteria value, recognising the comma as criteria-value delimiter, rather than as filter-value delimiter.