(API >=2.0.0): Data: Data queries full parameter support

[vlahona]

Introduce support for:

• Data Further Describing Results Parameters

1. attributes parameter, e.g. dsd, msd, dataset, series, obs, {attribute_id} (partial support "all" and "none" already implemented)
2. one or more measures in the request ({measure_id}) (partial support "all" and "none" already implemented)
3. operators on filters. include all the operators for filtering data by component value ("eq" already supported

• Data Identification Parameters

1. support multiple values for AGENCY and/or ID and/or VERSION