Remove betacloud from the list of providers (#1054)

The environment is retired and is no longer used.

Signed-off-by: Christian Berendt <[email protected]>

Author: berendt

_assets/images/logo-betacloud.png

@@ -1,9 +1,6 @@
 - name: "pluscloud open"
   image: "logo-pluscloud-open.svg"
   link: "https://www.plusserver.com/produkt/pluscloud-open/"
-- name: "Betacloud"
-  image: "logo-betacloud.png"
-  link: "https://www.betacloud.de/"
 - name: "Wavestack"
   image: "logo-wavestack.svg"
   link: "https://www.noris.de/wavestack-cloud"