implement filter API

[mhogeweg]

see: https://github.com/stac-api-extensions/filter

this extension implements CQL (common query language) that builds on OGC specs like OGC API Features and OGC API Records).

to support the Pro STAC client, implement the /collections/{collection_id}/queryables API as described in https://github.com/stac-api-extensions/filter?tab=readme-ov-file#queryables

this api shows up at the root /stac/queryables as well. at the root, the response includes queryables for all collections. in a collection it only returns queryables for that specific collection.

[as0050629]

@mhogeweg Please review https://github.com/Esri/geoportal-server-catalog/tree/684_StacFilterExtn