Add alternate domain for medienarchiv-zhdk (#819)

Author: urs-van-binsbergen

providers/medienarchiv-zhdk.yml

@@ -5,6 +5,7 @@
   - docs_url: http://madek.readthedocs.io/en/latest/development/embeds/
     schemes:
     - https://medienarchiv.zhdk.ch/entries/*
+    - https://zhdk.medienarchiv.ch/entries/*
     url: https://medienarchiv.zhdk.ch/oembed.{format}
     example_urls:
     - https://medienarchiv.zhdk.ch/oembed.json?url=https%3A%2F%2Fmedienarchiv.zhdk.ch%2Fentries%2Fda88e9e6-6b53-447b-8113-637d885f8ab2