Add additional sub commands for packagers

[eqrx]

What feature would you like to be added?
Cobra supports automatic generation of bash and zsh completions and man pages. To use this features, additional command needs to be created.

What are use cases of the feature?
While not critical from the use of Kubeone, these features add to the usability and overall quality of it. Bash completions. Man pages are providing a universal method for UNIX users to view the documentation quickly while completions help user to avoid unnecessary typing and lookups when the functions of commands is already known.

[xmudrii]

+1 from my side especially for autocompletions.

[xmudrii]

/lifecycle active
/assign eqrx