Enable authentication for Flame

[k82cn]

Motivation

Currently, we support TLS for security; but we also need to support authentication for isolation cross sessions.

Function Specification

flmadm is used to sign a token for a user, and then the user can use this token to connect to flame for session/application.

With the token, the user can only operate his sessions/applications. For admin, he can operate all sessions/applications.

Solutions

1. provide plugin machinary for different auth
2. impl jwt as default impl

Additional context

N/A