CQL2: ILIKE vs. CASEI

[m-mohr]

CQL2 has evolved and the ILIKE operator was removed from the specification. pgstac still implements ILIKE. Instead there's now a function called CASEI for a similar purpose. (ACCENTI might also be relevant.) Those are not yet implemented. This should probably be made specification compliant at some point.

Spec: https://github.com/opengeospatial/ogcapi-features/blob/master/cql2/standard/annex_ats_case-insensitive-comparison.adoc

Related issues:

• Case-insensitive string comparison opengeospatial/ogcapi-features#630
• CQL2-JSON: function instead of op for casei/accenti, temporalPredicate, spatialPredicate, arrayPredicate? opengeospatial/ogcapi-features#828