Add node commands (doctor, verify, ...)

[filoozom]

• /node doctor ip:port

  • Checks if the node is online (accepts connections on ip:port)
  • Check if the API port is correctly closed or filtered
  • Check if it's running a fairly recent version (we can only check if it's using the latest handshake protocol at this point)
  • Check if it's running on the right chain
  • Make sure the node is funded (check if the overlay address deployed a contract)
  • Check if the node is running in light or full mode and tell the user

• /node verify ip:port

  • Send a random string to the user with detailed instructions of how to insert it in their welcome message
  • When it's done, and the command is re-issued, connect to the node and check if the welcome message contains the given string
  • If so, give the user the node-operator role
  • If not, send the same message as in the first step

[significance]

this is great 👌