Add database contraint to ensure that current_landuse_order and current_landuse_group are set together

[matkoniecz]

        SELECT
            geometry_id,
            current_landuse_order,
            current_landuse_group
        FROM
            buildings
        WHERE
            current_landuse_order IS NOT NULL AND
            (current_landuse_group IS NULL OR cardinality(current_landuse_group) = 0);

reports some entries (I am fixing them).

While right now interface block such invalid data, it would be preferable to ensure that it would be blocked also on database level

[polly64]

@matkoniecz can this be closed?

[matkoniecz]

no, it still needs to be done