feat(greenhousectl) cluster re-onboard updates token

[kengou]

Description

greenhousectl cluster bootstrap ... now supports updating tokens for existing clusters. The same command needs to be re-executed then the token will be updated in the Secret

Changes in greenhousectl cluster bootstrap based on the received feedbacks:

• free-access-mode Flag retired
• bootstrap-kubeconfig is now kubeconfig
• • --kubeconfig is expected to point to the cluster which will be onboarded. This parameter does not need to be set. if KUBECONFIG env var is set that will be used
• NEW FLAG--greenhouse-kubeconfig needs to be set, to point to your greenhouse cluster

greenhousectl cluster bootstrap only expects mandatory parameters: org, greenhouse-kubeconfig

What type of PR is this? (check all applicable)

• 🍕 Feature
• 🐛 Bug Fix
• 📝 Documentation Update
• 🎨 Style
• 🧑‍💻 Code Refactor
• 🔥 Performance Improvements
• ✅ Test
• 🤖 Build
• 🔁 CI
• 📦 Chore (Release)
• ⏩ Revert

Related Tickets & Documents

• Pre-requisite feat(clusterController): check actual token validity #657

Added tests?

• 👍 yes
• 🙅 no, because they aren't needed
• 🙋 no, because I need help
• Separate ticket for tests # (issue/pr)

Please describe the tests that you ran to verify your changes. Provide instructions so we can reproduce. Please also list any relevant details for your test configuration

Added to documentation?

• 📜 README.md
• 🤝 Documentation pages updated
• 🙅 no documentation needed
• (if applicable) generated OpenAPI docs for CRD changes

Checklist

• My code follows the style guidelines of this project
• I have performed a self-review of my code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes