Add possibility to display the server version

[ThomasCAI-mlv]

Problem

The central team managing the server component (ns4kafka) and the teams managing each namespace are often not the same. Outside of the central team, it is not currently possible to know which version of ns4kafka is deployed, and so which version of kafkactl should be used, when there is no clear documentation maintained by the central team.

Suggestion

The command line kafkactl -v should display the server version, in addition to the kafkactl version that we currently have.
An output like the following could be good:

Client Version: v1.14.0
Server Version: v1.13.1

Additional Context

The feature in kubectl is like such:

> kubectl version --short
Client Version: v1.27.16
Kustomize Version: v5.0.1
Server Version: v1.30.7