[FEAT cloudctl] - Refactor cluster-version subcommand #85

Priority

(Medium) I'm annoyed but I'll live

User Story

Right now, whole functionality or checking cluster version is combined in the single function, which returns only a possible error of a Printer, which is also calculated in the same function.

Description

This issue is about extracting/separating the functionality of cluster version checking (which then can be e.g. used in implementation of #72 which depends on guessing the cluster version) from the final writing the output to subcommand output.

Acceptance Criteria

• Code refactored to move the main functionality into internal/ClusterVersion function which then could be consumed by subcommand defined in cmd/
• Unit tests refactored to skip testing the functionality through cobra.Command interface to more granular units.

Reference Issues

Should be done probably after #84