Validate the status of config_db.json after Redis modification

[byteocean]

Summary

Currently, the configuration, e.g., ports' admin state, is done via the interaction between agent and Redis db. As the switch can be also configured via config_db.json, which should run on top. It is needed to check if the status of config_db.json can be keep consistent automatically once configuration is written into the Redis db. It is helpful to maintain a global consistent state.