Right now, WDQS assumes for it's default prefix/URL system that entity and predicate prefixes come from the same host. This influences both default prefixes and more importantly, URIs for dictionaries and inlining. We should enable WDQS to be able to handle scheme where entity URIs may come from different places, e.g. mixing entity with wd: prefix for wikidata and sdc: prefix for commons.
For default prefixes, we can just add a config, but we also may want the inlining to work for both URI schemes, which may require some additional support.
The goals to achieve are:
- Have sdc: items and data triples recognized by Munger/Updater as proper entities.
- Have all SDC URIs be properly inlined.
- Have Updater handle all statements properly
- Have sdc: and sdcs: prefixes to work by default.
We still need to have single URI for:
- statement prefix (Updater assumes there's single statement prefix)
- property prefixes
- Entity ID <-> URI conversion, can be different for different URIs.