Implement a passive Discord Bot to grant user Citizen role

[ken-futureverse]

Our current implementation #21 only works if user has joined CENNZnet server before, for non-joining users, we need to provide a Bot service to handle the granting role process.

This is how the user flow roughly looks like

• User passes their wallet address to the bot
• The bot runs a check to make sure the account has correct identity set and is matched with the sender account
• Response with either success / error message