order=ASC|DESC to be correctly combined with the defined sort field

[fmigneault]

The proposed method by OGC API Features is to combine order into sortby using a prefix + or - before the field by which to sort. For example, sortby=+field,-other.

https://github.com/opengeospatial/ogcapi-features/blob/f810f6652c637cbc045e5baae726e83b9ccaa6d0/proposals/search/standard/schemas/query.json#L42-L49

Consider that CQL2 filter can also be employed for the sorting capability

• relates to Consider filter operations with filter-lang=cql-text|cql-json using CQL2 #640