Feature: Frontend: Lookup schema and suggest to check it

[dpriskorn]

As a user I want to check an item (e.g. https://www.wikidata.org/wiki/Q131318799) based on the schema stated with P12861 in the item for the class (https://www.wikidata.org/wiki/Q2143825 in this case) so I don't have to look it up myself
@salgo60 would you also like this?