feat(ske): add commands to trigger operations

[h3adex]

Description

This PR adds the following commands:

stackit ske cluster hibernate (added a prompt for confirmation)
stackit ske cluster wakeup
stackit ske cluster maintenance (added a prompt for confirmation)
stackit ske cluster reconcile

Checklist

• Issue was linked above
• Code format was applied: make fmt
• Examples were added / adjusted (see e.g. here)
• Docs are up-to-date: make generate-docs (will be checked by CI)
• Unit tests got implemented or updated
• Unit tests are passing: make test (will be checked by CI)
• No linter issues: make lint (will be checked by CI)

[rubenhoenle]

@h3adex finished the implementation for you so we can merge this soon :)