[STAC] trailing slash management

[pvgenuchten]

Description

This is a follow-up of geopython/pygeoapi#97 and radiantearth/stac-browser#384 to indicate STAC contradictionary to ogcapi:records, expects a trailing slash when referencing a folder

This will impact how we build local links

Also a reference to verify that we include a proper self link on records, the latter is what we do, contradicitionary to pygeoapi, which may explain why the links to items on this page are actually operational

[m-mohr]

STAC doesn't require a trailing slash, you are refering to an outdated version.
Latest version: https://github.com/radiantearth/stac-spec/blob/master/best-practices.md#consistent-uris

STAC simply follows RFC 3986 for resolving relative URIs against a base URL (i.e. self link)