1. understand and rewrite the attached code (https://1drv.ms/u/s!AidJC3PD0CHZpqd

1. understand and rewrite the attached code (https://1drv.ms/u/s!AidJC3PD0CHZpqdRshGDoU2IWGmHhA?e=lpTkDb) (check included mp4 demo);
2. when starting main app, besides blockchain initailization, the mininet visual topology needs to be generated too.
3. each time clicking button (enable or disable) device, it calls blockchain and triggers the devices changes on mininet topology(mininet_rest.py connection drops or reconnect). Currently it only called blockchain.
4. change the UI to make device controllers look and feel similar to actual mininet visual topology