This diff introduces an integrational tests call for the Tunnelbroker API:
1. We are checking for the wrong formatted `deviceID`: the server should return an error.
2. Generating a keypair for making a signature.
3. Getting a string to be signed from the Tunnelbroker server for the `deviceID`.
4. Checking for the server error in case the provided signature is wrong.
5. Create a new session (getting `sessionID`) by calling the Tunnelbroker new session API call.
Linear task: [[ https://linear.app/comm/issue/ENG-1657 | ENG-1657 ]]