Topology Mutation Hook implementation

[sbueringer]

Implementation umbrella issue for #6319
As the proposal (#6349) has been merged, we can start with the implementation now.

Done:

• Add API types
  • PR: ✨ Topology Mutation: Add types for Topology Mutation Hook #6514 (@sbueringer)
• Refactor inline patching to use the new API types
  • PR: ✨ Topology Mutation: use API types for inline patching #6289 (@sbueringer)
• Implement external patches (+ add fields to ClusterClass CRD + e2e test)
  • PR: ✨ Topology Mutation Hook: Implement external patching #6623 (@killianmuldoon)
• Follow-up for more unit test coverage (🌱 Add tests for external patch apply #6658 @killianmuldoon)
• book: documentation (📖 Runtime SDK: extend documentation & update proposals accordingly #6756 @sbueringer)

TODO before v1.2.0 release:

-

/kind feature
/area runtime-sdk

[sbueringer]

Feature has been completed. I opened follow-up tasks for some e2e test improvements (#6859) and clusterctl support (#6860).

Thx for the great work everyone!

/close

[k8s-ci-robot]

@sbueringer: Closing this issue.

In response to this:

Feature has been completed. I opened follow-up tasks for some e2e test improvements and clusterctl support.

Thx for the great work everyone!

/close

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository.