Improve CNI installer

**What would you like to be added**:

Currently cni installer is within the kmesh daemon, however when the daemon panic unexpected, the cni does not have a chance to uninstall all the cni configs.

If the kubeconfig kmesh-cni using is not out of date, then after kmesh-daemon updated, it can start up successfully.
However if the kubeconfig's token is out dated, the the above procedure would fail.

Several solutions come up to my mind:

1. Do clean up the cni config at the end of https://github.com/kmesh-net/kmesh/blob/main/build/docker/start_kmesh.sh#L54
2. Add a go routine in cni installer, watch the token file, update the kubeconfig when token modified. This would make sure the kubeconfig can not expire easily.
3. Make kmesh-cni `CmdAdd` never fail, even it failed, we return success. And depend on manage controller to manage workload eventually.

**Why is this needed**:

Read build/docker/start_kmesh.sh at line 54 and locate the CNI installer and kmesh-cni CmdAdd path. Compare the three proposed approaches around daemon panic cleanup, kubeconfig token refresh, and CmdAdd failure handling; clarify which behavior is intended and define completion checks for that choice.

Written by the indexing model from the issue text.