content/events.json: Remove past special events

      "name_de": "Spezielle Events",

      "name_en": "Special Events",

      "events": [

        {

          "start": "2019-02-09 13:30",

          "duration": "3h",

          "location": "CERN",

          "summary_en": "The Chaostreff Bern visits the CERN",

          "summary_de": "Unser Ausflug ans CERN",

          "title_de": "CERN Besuch",

          "title_en": "CERN Visit",

          "url_de": "/de/cern-besuch.html",

          "url_en": "/en/cern-visit.html"

        },

        {

          "start": "2019-03-16 14:00",

          "duration": "10h",

          "location": "Kyburgstrasse 13,3013 Bern",

          "summary_en": "Opening party of our hackerspace",

          "summary_de": "Eröffnungsfeier unseres Hackerspaces",

          "title_de": "Eröffnung Hackerspace",

          "title_en": "Hackerspace Opening Party",

          "url_de": "/de/einweihung_kyburgstrasse_13_einladung.html",

          "url_en": "/en/einweihung_kyburgstrasse_13_einladung.html"

        }

      ]

    }

  ]