Document Watcher Certificate Setup (CM vs GCM)

Description

Document the certificate setup including rotation mechanism. Depict the overall setup and what is equal between GCM and cert-manager. Show the differences between GCM and cert-manager.

Reasons

Understanding of the overall setup and its details need to be understandable.

AC

• decide whether the doc should live at lifecycle-manager or runtime-watcher
• decide whether it is an extension to https://github.com/kyma-project/runtime-watcher/blob/main/docs/architecture.md, or if this current doc should be split into two or more parts
  • e.g., one part focussing on the certificate setup, another one focusing on how to configure the watch
• use the exact terminology aligned here: https://github.com/kyma-project/lifecycle-manager/issues/2425
• describe the overall setup including rotation applicable to both solutions
• describe where the two solutions differ (e.g. renewal of SKR certs)

Read docs/architecture.md in runtime-watcher and the terminology in lifecycle-manager issue 2425. First decide whether the documentation belongs in lifecycle-manager or runtime-watcher and whether it should be split. Done means the docs explain the shared certificate setup and rotation, plus the differences between GCM and cert-manager, including SKR certificate renewal.