Doc: add simulator limitation and common pitfalls

[bk201]

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.