Enhance token authentication mechanism

[un-lock-able]

This PR adds two new features:

1. Allow the user to specify the expriry time of a worker token upon worker startup, and allow a worker token to valid forever;
2. Make retaining the token the default behavior when user logs in, and adds refresh command to request a new token, a revoke command to revoke all tokens.

[BobAnkh]

Let's first align the following things and then I will review the rest of the code. Also, please update all relevant documents.

[un-lock-able]

@BobAnkh I have removed the custom serde functions and now worker's lifetime is default to None, and user can override the setting by cmd or config file.

[BobAnkh]

Need to improve the credential system. We might wait for the feature of address storage cred system to merge together.

[BobAnkh]

This function is a little bit weird and needs modification.

[BobAnkh]

We might need some discussion on that before any changes are taken.

[BobAnkh]

Maybe we doesn't need to remove the file. We could just keep it empty, so just use the original code we already have in our modify_or_append_credential function, that is, write the content joined by "\n", as in your else block.