modified notary server: https://github.com/mhchia/notary-server/tree/work-with-extension

Changes
- websocket connection to notary-server
        - HTTP request to /session first and get sessionId
                - Craft it through web_sys
                - Send HTTP request with `fetch`
                        - Usually it's done with window, but in web worker there is no window
        - Use WebSocket API to establish wss connection to notary server
                - Chang notary-server to accept a param `sessionId`
                        - In browser there is no way to add headers, so we couldn't add "X-Session-Id"
- Prover config must use the session id returned from the notary server

Concerns
- Now we have to manually set notary server as trusted since the cert is self-signed.
        - rootCert couldn't be added when initiating HTTP request due to browser security config