Remove myopenid from openid providers
Let test_note_event pass in timezones other than +00:00
Fix off-by-one error in user notes list
Link the prefixed wikidata-tags to wikidata.org

With this commit, the prefixed wikidata-tags get linked to the
corresponding wikidata.org-page in the current interface-language.

Multiple semicolon-separated wikidata-IDs are shown as multiple
semicolon-separated links to wikidata.

This commit contains also some tests for those links.