Registers a chat command, xban_no_password that uses xban2 to ban all accounts with no password, or with the password equal to the username.

Accounts are banned with the messages "account has no password" or "account has a weak password". A player with a banned account can create a new account, and if they want access to their old one, can contact the admin (in game, via /mail), and if their current and previous historic IP addresses match, then I can (no promise that I will though) unban the account and force the user to set a password on it.

Ideally, a Minetest server would be configured with disallow_empty_password = true in its minetest.conf file.

Why does this mod exist? Because I assumed admin responsibilities over a semi-active public server that did not require passwords on user accounts. This server has ~19k accounts, ~10k with no password and ~100 with the password equal to the username. Along comes a malicious player who has compiled a list of recently active players and has been siezing control over their accounts. Worse, they are using a VPN, so banning IPs to stop the damage is not working. I wrote this mod to preserve the survivng accounts.