Doc: add simulator limitation and common pitfalls

When examining a support bundle with the simulator, there are some simulator-made changes, we need to document this in case engineers feel misleading.

- node taints.
  - Node will always have the taint:
    ```
    taints:
    - effect: NoSchedule
      key: node.kubernetes.io/not-ready
    ```
- uid is different. Simulator generates new uids when loading resources. 