Resolve "eolebase-k3d: the cluster does not work with 3 servers"

When creating the cluster with 3 servers, kubectl commands fail with the following error:

Error from server (InternalError): an error on the
server ("apiserver not ready") has prevented the request from
succeeding

• provisionning/ubuntu/eolebase.sh: create the cluster with only 1 server.

Closes #10 (closed)