Could not add Replica Set to MongoDB Shard
So i have found my mistake. I had to add the Servernames and IP Addresses to the hosts file of the docker container in which the config Servers runs. After that i could add my Replica Set as a Shard. I will edit this answer this or next week and provide a link to a Blogpost in which i will describe how to make a MongoDB Sharding with Docker on Virtual Machines.