Generate Wikidata cards for multiple performers and ensembles

Generate Wikidata cards for multiple performers and ensembles

Uses real-time Wikipedia description lookups, in English-only, to
provide the first sentence of the Wikipedia description of the
performer, as well as a link to the related Wikipedia page via the WP
icon.

Wikicards are built up from properties using a generic function; see the
Twitter, Facebook, and Musicbrainz properties for examples.

Signed-off-by: Dan Scott <dscott@laurentian.ca>