Add 23M GmbH to users.mdx (#375)

Author: dataCobra

src/pages/users.mdx

@@ -16,6 +16,7 @@ page](https://github.com/apache/cloudstack-www/blob/main/src/pages/users.mdx) to
 add or remove your organisation. You may also write your concerns to our users
 mailing list <b>users@cloudstack.apache.org</b>.
 
+- [23M GmbH](https://23M.com)
 - [ActOnMagic](http://www.actonmagic.com)
 - [Apiculus](https://apiculus.com)
 - [Appcore](http://www.appcore.com)