Automatic linking of Wikidata/Wikipedia entries
Description
Essentially a duplicate of #5838. I'm trying to verify operator:wikidata/operator:wikipedia, and not being able to click the links makes the checking a lot slower. I instead open the normal OSM viewer for the object which links to Wikidata/Wikipedia for the relevant tags.
The URL generation could be obtained from the OpenStreetMap wiki, e.g. Property P8 "formatter URL" of Q99 "brand:wikidata" is "http://www.wikidata.org/entity/$1".
Screenshots
By @nyurik, in https://github.com/openstreetmap/iD/issues/5838#issuecomment-45989162:

openstreetmap/id-tagging-schema#769 would add an “Operator Wikidata” field that would come with an external link button.
I don't have the time to read further into this but it would be much appreciated if someone could make this happen. For me, adding a link button to everything *:wikidata would be ideal, but any other approach that adds a link to a wikidata fields is fine with me.
Edit: I have a search shortcut in Firefox which links to https://www.wikidata.org/w/index.php?title=Special%3ASearch&search={input here, any Wikidata id works}
There is only a bit of an issue with how the UI is currently displaying these fields: Adding the same field for all currently used *:wikidata/wikipedia fields would really overload the sidebar. So, it must also be accompanied with some form of a more compact UI field, maybe one that includes all related fields with each other, e.g. brand + brand:wikidata + brand:wikipedia.